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for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim?s website at www.maximintegrated.com. li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/ MAX8895X/max8895y evaluation kit available 19-5205; rev 4 9/12 ordering information and typical operating circuit appear at end of data sheet. general description the max8895_ usb-compliant linear battery chargers operate from either a usb port or dedicated charger with automatic detection of adapter type and usb enumera - tion capability. the max8895_ integrate the battery dis - connect switch, current-sense circuit, mosfet pass ele - ments, and thermal regulation circuitry, and eliminate the external reverse-blocking schottky diode to create the simplest and smallest stand-alone charging solutions. the max8895_ includes an automated detection of charge adapter type, making it possible to distinguish between usb 2.0 device, usb charger, and dedicated charger devices. furthermore, the max8895_ include a usb enumeration function that automatically negotiates with a usb host, making it possible to achieve the highest current available from a usb 2.0 device or usb charger without processor intervention. the adapter type detec - tion is compliant with usb 2.0 specification as well as usb charging revision 1.1. the max8895_ controls the charging sequence for single- cell li+ batteries from initial power-ok indication, through prequalification, fast-charge, top-off, and finally charge termination. charging is controlled using constant cur - rent, constant voltage, and constant die-temperature (cccvctj) regulation for safe operation under all condi - tions. the maximum charging current is adaptively con - trolled by subtracting the system current from the input current limit, ensuring that the charging current is always maximized for any given operating condition. the max8895_ features optimized smart power control to make the best use of limited usb or adapter power. battery charge current is set independently of the sys_ input current limit. power not used by the system charges the battery. automatic input selection switches the system from battery to external power. this allows the application to operate without a battery, discharged battery, or dead battery. other features include undervoltage lockout (uvlo), overvoltage protection (ovp), charge status flag, charge fault flag, power-ok monitor, battery thermistor monitor, charge timer, and a 3.3v output. the max8895_ operates from a +4.0v to +6.6v sup - ply and include overvoltage protection up to +16v. the max8895_ is specified over the extended temperature range (-40 n c to +85 n c) and are available in a compact 2.36mm x 2.36mm, 25-bump wlp package (0.4mm pitch). features s enables charging from a usb port* s automatic detection of adapter type s enumeration capability without processor intervention s usb low-speed operation without external crystal (max8895v/max8895w/MAX8895X) s usb full-speed operation using an external crystal (max8895y) s compliant with usb 2.0 specification s compliant with usb charging specification (revision 1.1) s adaptive input current limit for dedicated charger s input overvoltage protection to 16v s automatic current sharing between battery charging and system s smart power selector k allows operation with discharged or no battery s ntc monitoring of battery temperature s no external mosfets required s thermal regulation prevents overheating s 2a shutdown current s tiny 2.36mm x 2.36mm, 25-bump, 0.4mm pitch wlp package applications bluetooth ? headsets charging cradlesportable devices smart power selector is a trademark of maxim integrated products, inc. * protected by us patent #6,507,172. bluetooth is a registered trademark of bluetooth sig. downloaded from: http:///
2 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y stresses beyond those listed under ?absolute maximum ratings? may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. bus_ to agnd ................................................... -0.3v to +16.0v xin, xout, int_3v3 to agnd ............................. -0.3v to +4.0v enu_en, sus_en, rwu, d+, d-, preq , chg , uok , flt , bat_, sys_, cen , stdby, det_done , ibus_def, chg_type to agnd ..................... -0.3v to +6.0v kb_tm, iset, thm, idn, ct to agnd ................................... -0.3v to (v int_3v3 + 0.3v) dgnd to agnd .................................................. -0.3v to + 0.3v i bus_ , i bat_ , and i sys_ continuous current ........... 1800ma rms continuous power dissipation (t a = +70 n c) 25-bump, 2.36mm x 2.36mm wlp (derate 19.34mw/ n c above +70 n c) .......................... 1560mw operating temperature ...................................... -40 n c to +85 n c junction temperature ..................................................... +150 n c storage temperature range ............................ -65 n c to +150 n c soldering temperature (reflow) ...................................... +260 n c electrical characteristics (thm = cen = sus_en = agnd, v bat_ = 4.2v, v bus_ , ct, preq , chg , uok , flt, det_done are unconnected, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at t a = +25 n c.) (note 1) absolute maximum ratings parameter symbol conditions min typ max units usb-to-sys preregulator usb operating range initial v bus_ voltage before enabling charger 4.0 6.6 v usb standoff voltage v bat_ = v sys_ = 0v, i bus_ < 650 f a (max) 14 v bus_ok debounce timer t usb_db time from bus_ within valid range until uok logic-low 500 650 ms usb undervoltage lockout threshold uok logic-low, v bus_ rising, 100mv hysteresis before initial detection of external device 3.85 4.0 4.15 v uok logic-low, v bus_ falling usb 2.0 low-power device 3.75 3.9 4.05 uok logic-low, v bus_ falling usb 2.0 high-power device 3.95 4.1 4.25 uok logic-low, v bus_ falling dedicated charger or usb charger v sys _ - 100mv v sys_ + 50mv v sys_ + 200mv usb overvoltage protection threshold uok logic-low, v bus_ rising, 100mv hysteresis 6.8 6.95 7.1 v usb input supply current(note 2) i detect charge type detection,i sys_ = i bat_ = 0ma, v cen = 0v max8895v/max8895w/ MAX8895X 0.5 ma max8895y 2.5 i enumerate usb 2.0 enumeration in progress, i sys_ = i bat_ = 0ma, v cen = 0v 100 i suspend suspend mode, i sys_ = i bat_ = 0ma, v stdby = 3.3v max8895v/max8895w/ MAX8895X 0.5 max8895y 2.5 i usb_100ma usb 2.0 low-power device detected t a = 0 n c to +85 n c 100 t a = -40 n c to +85 n c 102.5 i usb_500ma usb 2.0 high-power device detected 500 usb input current limit i sus during suspend 0 ma i enu during usb enumeration 40 45 55 i usb_lp usb 2.0 low-power device detected 80 90 98 i usb_hp usb 2.0 high-power device detected 460 475 490 downloaded from: http:///
3 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y electrical characteristics (continued)(thm = cen = sus_en = agnd, v bat_ = 4.2v, v bus_ , ct, preq , chg , uok , flt, det_done are unconnected, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at t a = +25 n c.) (note 1) parameter symbol conditions min typ max units v bus_ -to-v sys_ on- resistance v bus_ = v cen = 5v, i sys_ = 400ma 200 320 m i v sys_ -to-v bat_ reverse regulation when sys is in regulation and charging stops, v sys_ falling, 50mv hysteresis v bat_ - 80mv v bat_ - 50mv v bat_ - 20mv v input limiter soft-start time input current ramp time 50 100 f s thermal-limit start temperature t die_lim +110 n c thermal-limit start temperature hysteresis 10 n c thermal-limit gain i sys_ reduction/die temperature (above +110 n c) 5 %/ n c v bus_ adaptive current regulation threshold v bus_ regulation threshold where input current limit is regulated for dedicated charger or usb charger v sys_ + 440mv v sys_ + 550mv v sys_ regulation voltage v bat_ > 3.45v, i sys_ = 1ma to 1.6a, v bus_ = v cen = 5v v bat_ + 140mv v bat_ + 210mv v minimum sys regulation voltage v bus_ = 6v, i sys_ = 1ma to 1.6a, v cen = 5v 3.3 3.4 3.55 v charger bat_-to-sys_ on-resistance i sys_ = 200ma 55 80 m i bat_ undervoltage lockout v bat_uvlo_f v bat_ falling 2.60 2.85 3.1 v v bat_uvlo_r v bat_ rising 2.75 3.00 3.25 charger soft-start time charge-current ramp time 1 ms bat_ leakage current v bus_ not connected 2 6 f a v bus_ connected, v cen = 5v 2 6 precharge modebat_ precharge-current set range i pchg r iset = 30k i to 1.875k i , v bat_ >1.4v (note 3) i fchg /10 a bat_ prequalification threshold v bat_pchg_r v bat_ rising 2.7 2.8 2.9 v v bat_pchg_f v bat_ falling 2.6 2.7 2.8 fast-charge modebat_ charge-current set range i fchg r iset = 30k i to 1.875k i , v bat_ >1.4v (note 3) 0.1 1.85 a iset = int_3v3 (note 3) 600 ma bat_ charge-current accuracy, charger loop in control v bus_ = 5.5v (note 3) r iset = 1.875k i 0000 1850 0000 ma r iset = 5k i 540 600 660 r iset = 30k i 90 100 110 bat_ fast-charge threshold v bat_fchg_r v bat_ rising threshold, where charging current i fchg is reduced to i tchg 3.9 4.0 4.1 v v bat_fchg_f v bat_ falling threshold, where charging current is increased to i fchg 3.7 3.8 3.9 downloaded from: http:///
4 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y electrical characteristics (continued)(thm = cen = sus_en = agnd, v bat_ = 4.2v, v bus_ , ct, preq , chg , uok , flt, det_done are unconnected, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at t a = +25 n c.) (note 1) parameter symbol conditions min typ max units top-off charge mode top-off charge current i tchg r iset = 30k i to 1.875k i (note 3) 0.6 x i fchg a bat_ charge termination current range i chg_done r idn = 240k i to 15k i 10 160 ma idn = int_3v3 80 bat_ regulation voltage v bat_reg i bat_ = 0ma t a = +25 n c 4.179 4.200 4.221 v t a = 0 n c to +85 n c 4.158 4.200 4.242 bat_ recharge threshold v bat_rechg recharge threshold in relation to v bat_ in done state going into top-off mode (figure 20) -100 -200 -300 mv charge timer maximum prequalification time t pchg from v cen falling to end of prequalification charge mode, v bat_ = 2.5v c t = 0.068 f f 16 min c t = agnd 20 maximum fast-charge time t fchg from v cen falling to v flt falling c t = 0.068 f f 100 min c t = agnd 120 maintain-charge time t mtchg c t = 0.068 f f 4 min c t = agnd 5 timer accuracy c t = 0.068 f f -30 +30 % c t connected to agnd -30 +30 timer extend threshold percentage of charge current below which timer clock operates at half speed 50 % timer suspend threshold percentage of charge current below which timer clock pauses 20 % adapter type detection d- current sink i dm_sink max8895v/MAX8895X/max8895y 50 86 150 f a max8895w 64 86 102 d+ source voltage v dp_src i dp_src = 0 to 200 f a 0.5 0.6 0.7 v d+ detection threshold v dat_ref 0.25 0.32 0.40 v d+ source on-time t dp_src_on 100 ms d+ source to high current time t dp_src_hc 40 ms d- pullup resistor r dm_pu max8895v/max8895w/MAX8895X only, external series resistor = 33 i 1.425 1.500 1.575 k i d+ pullup resistor r dp_pu max8895y only, external series resistor = 33 i 1.425 1.500 1.575 k i d+ charger detectionpullup resistor r dp_cd_pu r dp_cd_pu connect to int_3v3 200 330 600 k i d- weak current sink i dm_cd_pd 0.1 f a d- logic-high threshold v dm_ih 0.8 2.0 v downloaded from: http:///
5 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y electrical characteristics (continued) (thm = cen = sus_en = agnd, v bat_ = 4.2v, v bus_ , ct, preq , chg , uok , flt, det_done are unconnected, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at t a = +25 n c.) (note 1) parameter symbol conditions min typ max units enumeration time limit t enum time from start of enumeration process until enumeration must be completed; if not completed, the max8895_ retries to enumerate 10 s reconnect timer t fault time from failed enumeration to adapter type detection reenabled 3 s enumeration fail to reconnect timer t enu_fault time from enumeration fail at 500ma until enumeration is retried at 100ma or time from enumeration fail at 100ma until reconnect timer is started 87 ms reenumeration timer t re_enum time from when the max8895_ has entered suspend mode until it reenumerates, rwu = agnd 100 ms oscillator frequency accuracy max8895v/MAX8895X only (internal oscillator), t a = +25 n c 5.91 6.00 6.09 mhz xin input current max8895y only, v xin = v stdby = 3.3v 10 f a xin logic-high input voltage max8895y only 2/3x v int_3v3 v int_3v3 v xin logic-low input voltage max8895y only 0.4 v thm thm cold threshold t amb_cold when charging is suspended, rising threshold, 2% hysteresis 72 74 76 % of v int_3v3 thm hot threshold t amb_hot when charging is suspended, falling threshold, 2% hysteresis 26 28 30 % of v int_3v3 thm threshold, disabled when thm function is disabled, falling threshold, 2% hysteresis 3 % of v int_3v3 thm input leakage thm = agnd or int_3v3 t a = +25 n c -0.1 0.001 +0.2 f a t a = +85 n c 0.01 logic i/o: chg , flt , uok , cen , preq , kb_tm, rwu, stdby, sus_en, enu_en, det_done, chg_type, ibus_def logic-input threshold high level 1.3 v low level 0.4 hysteresis 50 mv logic-input leakage current v bus_ = 0 to 5.5v t a = +25 n c 0.001 1 f a t a = +85 n c 0.01 logic-low output voltage ( chg , flt , uok , preq, det_done, chg_type only) sinking 10ma 35 100 mv logic-high output-leakage current ( chg , flt , uok , preq , det_done, chg_ type only) v sys_ = 5.5v t a = +25 n c 0.001 1 f a t a = +85 n c 0.01 downloaded from: http:///
6 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y note 1: specifications are 100% production tested at t a = +25 n c. limits over the operating temperature range are guaranteed by design and characterization. note 2: sum of input current limit and current used for int_3v3. note 3: maximum charging current is adaptively regulated to i in_lim - i sys_ with a maximum value of i chg . note 4: all devices are 100% production tested at t a = +25 n c. limits over the operating temperature range are guaranteed by design. note 5: guaranteed by design, not production tested. electrical characteristics (continued) (thm = cen = sus_en = agnd, v bat_ = 4.2v, v bus_ , ct, preq , chg , uok , flt, det_done are unconnected, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at t a = +25 n c.) (note 1) parameter symbol conditions min typ max units usb data interfacedifferential-receiver input sensitivity |v d+ - v d- | 0.2 v differential-receiver common-mode voltage 0.8 2.5 v d+, d- input impedance 300 k i d+, d- output low voltage v ol r load = 1.5k i from v d- to 3.6v 0.3 v d+, d- output high voltage v oh r load = 15k i from d+ and d- to agnd 2.8 3.6 v driver output impedance excludes external resistor 2 7 11 i bus_ idle time t idle only valid when an adapter type is detected as a usb 2.0 device; time bus_ is inactive until charging current is reduced to i suspend 3 ms usb host remote wake-up timer t rwu time delay from when the max8895_ is put into suspend mode until they request the host for a remote wake-up 100 ms d+, d- rise time(note 5) t rise max8895v/max8895w/MAX8895X only, c l = 50pf to 600pf, (figures 5 and 6) 75 250 ns max8895y only, c l = 50pf (figures 5 and 6) 4 20 d+, d- fall time(note 5) t fall max8895v/max8895w/MAX8895X only, c l = 50pf to 600pf (figures 5 and 6) 75 250 ns max8895y only, c l = 50pf (figures 5 and 6) 4 20 rise-/fall-time matching(note 5) max8895v/max8895w/MAX8895X only, c l = 50pf to 600pf (figures 5 and 6) 80 120 % max8895y only, c l = 50pf (figures 5 and 6) 90 110 output-signal crossover voltage (note 5) max8895v/max8895w/MAX8895X only, c l = 50pf to 600pf (figures 5 and 6) 1.3 2.0 v max8895y only, c l = 50pf (figures 5 and 6) 1.3 2.0 int_3v3 regulator int_3v3 voltage v bus_ = 5v, i int_3v3 = 0 to 10ma 3.0 3.3 3.6 v esd protection (d+, d-, v bus_ ) human body model v bus_ bypassed with 1 f f to agnd q 8 kv downloaded from: http:///
7 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y typical operating characteristics (v bat_ = 4.2v, v bus_ = 5v, iset = idn = ct = sus_en = int_3v3, stdby = enu_en = rwu = cen = kb_tm = agnd, circuits of figures 4 and 5 (max8895v/MAX8895X and max8895y, respectively), t a = +25 n c, unless otherwise noted.) max8895v/w/x v bus_ input supply current vs. v bus_ (suspend mode) max8895w/x/y toc01 v bus_ (v) input supply current (a) 14 12 2 4 6 8 10 50 100 150 200 250 300 350 400 0 01 6 sus_en = enu_en = cen = agnd stdby = int_3v3 max8895y v bus_ input supply current vs. v bus_ (suspend mode) max8895w/x/y toc04 v bus_ (v) input supply current (a) 14 12 8 10 4 6 2 50 100 150 200 250 300 350 400 450 500 0 01 6 cen = stdby = agnd max8895v/w/x v bus_ input supply current vs. v bus_ (charger enabled) max8895w/x/y toc02 v bus_ (v) input supply current (ma) 14 12 10 8 6 4 2 0.5 1.0 1.5 2.0 2.5 0 01 6 batt unconnectedsus_en = enu_en = cen = agnd max8895y v bus_ input supply current vs. v bus_ (charger enabled) max8895w/x/y toc05 v bus_ (v) input supply current (ma) 14 12 8 10 4 6 2 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0 01 6 battery unconnectedcen = agnd max8895v/w/x v bus_ input supply current vs. v bus_ (charger disabled) max8895w/x/y toc03 v bus_ (v) input supply current (ma) 14 12 10 8 6 4 2 0.5 1.0 1.5 2.0 2.5 0 01 6 v bat_ = 4.2v cen = int_3v3 sus_en = enu_en = agnd max8895y v bus_ input supply current vs. v bus_ (charger disabled) max8895w/x/y toc06 v bus_ (v) input supply current (ma) 14 12 8 10 4 6 2 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0 01 6 v bat_ = 4.2v cen = int_3v3 battery leakage current vs. battery voltage max8895w/x/y toc07 v batt (v) leakage current (a) 4.0 3.5 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 3.0 4.5 bus_ unconnectedcen = agnd battery leakage current vs. temperature max8895w/x/y toc08 temperature ( n c) leakage current (a) 60 35 10 -15 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 -40 85 charge current vs. battery voltage (dedicated charter) max8895w/x/y toc09 battery voltage (v) charge current (ma) 4.0 3.5 3.0 2.5 100 200 300 400 500 600 700 0 2.0 4.5 enu_en = sus_en = agnd, r iset = 5k i downloaded from: http:///
8 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y typical operating characteristics (continued) (v bat_ = 4.2v, v bus_ = 5v, iset = idn = ct = sus_en = int_3v3, stdby = enu_en = rwu = cen = kb_tm = agnd, circuits of figures 4 and 5 (max8895v/MAX8895X and max8895y, respectively), t a = +25 n c, unless otherwise noted.) charge current vs. battery voltage (low-power usb) max8895w/x/y toc10 battery voltage (v) charge current (ma) 4.0 3.5 3.0 2.5 10 20 30 40 50 60 70 80 90 100 0 2.0 4.5 enu_en = int_3v3, sus_en = agnd charge current vs. battery voltage (high-power usb) max8895w/x/y toc11 battery voltage (v) charge current (ma) 4.0 3.5 3.0 2.5 100 200 300 400 500 600 0 2.0 4.5 enu_en = sus_en = agnd charger in dropout charge current (dedicated charger) vs. ambient temperature max8895w/x/y toc12 temperature ( c) charge current (ma) 60 35 10 -15 601 602 603 604 605 606 607 608 609 610600 -40 85 battery regulation voltage vs. ambient temperature max8895w/x/y toc13 temperature ( c) battery regulation voltage (v) 60 35 10 -15 4.185 4.190 4.195 4.200 4.205 4.210 4.2154.180 -40 85 sys_ output voltage vs. v bus_ max8895w/x/y toc14 v bus_ (v) sys_ output voltage (v) 7 6 5 4 4.100 4.125 4.150 4.175 4.200 4.225 4.250 4.275 4.300 4.325 4.350 4.375 4.4004.075 38 i sys_ = 0ma i sys_ = 20ma v bat_ = 4.2v sys_ output voltage vs. battery voltage max8895w/x/y toc15 v batt (v) sys_ output voltage (v) 4.0 3.5 3.0 2.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0 2.0 4.5 i sys_ = 100ma v bus_ = 5v i sys_ = 0a sys_ dropout voltage vs. load current max8895w/x/y toc16 i sys_ (ma) sys_ dropout voltage (mv) 1500 1000 500 20 40 60 80 100 120 140 0 0 2000 bus_ unconnecteddropout measured when sys_ decreases by 10% sys_ output voltage vs. load current (high-power usb mode) max8895w/x/y toc17 i sys_ (ma) sys_ output voltage (v) 1500 1000 500 3.90 4.00 4.10 4.20 4.30 4.403.80 0 2000 system load switch in dropout v sys_ supplemented by v bus_ v bat_ = 4.2v sys_ output voltage vs. load current (dedicated charger) max8895w/x/y toc18 i sys_ (ma) sys_ output voltage (v) 1500 1000 500 3.95 4.00 4.05 4.10 4.15 4.20 4.25 4.30 4.35 4.403.90 0 2000 system load switch in dropout v sys_ supplemented by v bus_ v bat_ = 4.2v, nokia ac-10u downloaded from: http:///
9 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y typical operating characteristics (continued) (v bat_ = 4.2v, v bus_ = 5v, iset = idn = ct = sus_en = int_3v3, stdby = enu_en = rwu = cen = kb_tm = agnd, circuits of figures 4 and 5 (max8895v/MAX8895X and max8895y, respectively), t a = +25 n c, unless otherwise noted.) int_3v3 voltage vs. bus_ voltage max8895w/x/y toc19 v bus_ (v) v int_3v3 (v) 7.0 6.0 5.0 4.0 3.05 3.10 3.15 3.20 3.25 3.30 3.353.00 3.0 8.0 100ma charge current v bat_ = 4v 50ma charge current charge profile (usb 2.0 charger) max8895w/x/y toc21 time (min) v batt (v) 275 250 200 225 50 75 100 125 150 175 25 3.40 3.50 3.60 3.70 3.80 3.90 4.00 4.10 4.20 4.303.30 50 100 150 200 250 300 350 400 450 5000 0 300 v bat_ i bat_ motorola bc60 860mahc ct = 0.2f r iset = 3.74k i r idn = 243k i i batt (ma) time (x 10 -8 ) (s) d+, d- signals (v) 8.0 7.0 5.0 6.0 2.0 3.0 4.0 1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 max8895y eye diagram max8895w/x/y toc23 charge profile (nokia ac-10 charger) max8895w/x/y toc20 time (min) v batt (v) i batt (ma) 275 250 25 50 75 125 150 175 200 100 225 3.60 3.70 3.80 3.90 4.00 4.10 4.20 4.303.50 0 300 1000900 800 700 600 500 400 300 200 100 0 motorola bc60 860mahc ct = 0.2f r iset = 1.87k i r idn = 243k i v bat_ i bat_ time (x 10 -7 ) (s) d+, d- signals (v) 6.0 5.0 1.0 2.0 3.0 4.0 0.1 0.6 1.1 1.6 2.1 2.6 3.1 3.6 0 max8895v/w/x eye diagram max8895w/x/y toc22 max8895w/x/y toc24 0v0v 5v/div5v/div 5v/div5v/div 0v0v v d- v d+ v sys v bus 200ms/div dedicated charger connect downloaded from: http:///
10 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y typical operating characteristics (continued) (v bat_ = 4.2v, v bus_ = 5v, iset = idn = ct = sus_en = int_3v3, stdby = enu_en = rwu = cen = kb_tm = agnd, circuits of figures 4 and 5 (max8895v/MAX8895X and max8895y, respectively), t a = +25 n c, unless otherwise noted.) max8895w/x/y toc25 0v0v 0v 5v/div5v/div 5v/div 5v/div 0v v bat_ v sys_ v int_3v3 v bus_ 200ms/div r sys_ = 100 i dedicated charger disconnect max8895w/x/y toc27 0v0v 5v/div5v/div 5v/div500ma/div 0v0a v d- v d+ i bus v bus 400ms/div max8895y usb high-power 2.0 connect max8895w/x/y toc29 0ma0v 0v 5v/div2v/div 2v/div 200ma/div 0v v d- v d+ v bus_ i bus_ 2ms/div r sys_ = 100 i max8895y usb high-power 2.0 disconnect max8895w/x/y toc26 0v0v 5v/div5v/div 5v/div500ma/div 0v0a v d- v d+ i bus v bus 400ms/div max8895v/w/x high-power 2.0 max8895w/x/y toc28 0ma0v 0v 5v/div2v/div 2v/div 100ma/div 0v v d- v d+ v bus_ i bus_ 20ms/div r sys_ = 100 i max8895v/w/x usb high-power 2.0 disconnect max8895w/x/y toc30 0v0v 0ma 2v/div1v/div 200ma/div 2v/div 0v i bus_ v d+ v d- 1ms/div v flt max8895v/w/x usb autosuspend downloaded from: http:///
11 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y typical operating characteristics (continued) (v bat_ = 4.2v, v bus_ = 5v, iset = idn = ct = sus_en = int_3v3, stdby = enu_en = rwu = cen = kb_tm = agnd, circuits of figures 4 and 5 (max8895v/MAX8895X and max8895y, respectively), t a = +25 n c, unless otherwise noted.) max8895w/x/y toc31 0v0v 0ma 2v/div1v/div 200ma/div 2v/div 0v i bus_ v d+ v d- 1ms/div v flt max8895y usb autosuspend max8895w/x/y toc33 0v0ma 2v/div200ma/div 2v/div 2v/div 0v0v i bus_ v d+ v d- 1s/div v flt max8895y usb resume max8895w/x/y toc32 0v0v 0ma 2v/div1v/div 200ma/div 2v/div 0v i bus_ v d+ v d- 1s/div v flt max8895v/w/x usb resume prequalification timeout vs. ct capacitance max8895w/x/y toc34 c ct (pf) prequalification timeout (s) 80,000 60,000 20,000 40,000 200 400 600 800 12001000 1400 1600 0 0 100,000 fast-charge timeout vs. ct capacitance max8895w/x/y toc35 c ct (pf) fast-charge timeout (s) 80,000 60,000 40,000 20,000 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 0 0 100,000 downloaded from: http:///
12 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y pin configurations top view (bump side down) ab cd wlp e 1234 iset stdby bat_a sys_a bus_a idn chg bat_b sys_b bus_b enu_en preq uok kb_tm agnd sus_en rwu cen flt d+ ct thm int_3v3 dgnd d- 5 + max8895vMAX8895X top view (bump side down) ab cd wlp e 1234 iset stdby bat_a sys_a bus_a idn chg bat_b sys_b bus_b xin preq uok kb_tm agnd xout rwu cen flt d+ ct thm int_3v3 dgnd d- 5 + max8895y top view (bump side down) ab cd wlp e 1234 iset stdby bat_a sys_a bus_a idn chg_ type bat_b sys_b bus_b enu_en det_done uok kb_tm agnd sus_en i bus_def cen flt d+ ct thm int_3v3 dgnd d- 5 + max8895w downloaded from: http:///
13 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y pin description pin name function max8895w max8895v/ MAX8895X max8895y a1 iset iset iset maximum fast-charge current selection. connect a resistor from iset to agnd to set the fast-charge current from 0.1a to 1.85a. i fchg = 3000/r iset if iset is connected to int_3v3 the default i fchg is set as maximum charge current.iset can also be used to monitor the actual current charging the battery. see the monitoring charge current section for details. a2 stdby stdby stdby standby mode enable. connect stdby to agnd to enter automatic detect mode. in automatic detect mode, the max8895v/max8895w/MAX8895X determine when to enter suspend mode depending on the status of the sus_en logic input. when using the max8895y, the ic always starts in automatic suspend mode. connect stdby to int_3v3 or drive logic-high to force the max8895_ into suspend mode regardless of external conditions. a3 bat_a bat_a bat_a li+ battery connection (v bat_ ). connect a single-cell li+ battery from v bat_ to dgnd. the battery charges from v sys_ when a valid source is present at v bus_ . v bat_ powers v sys_ when v bus_ power is not present, or when the v sys_ load exceeds the input current limit. bypass v bat_ to dgnd with a 10 f f x5r or x7r ceramic capacitor. both bat_a and bat_b must be connected together externally. b3 bat_b bat_b bat_b a4 sys_a sys_a sys_a system supply output (v sys_ ). v sys_ is connected to v bat_ through an internal 55m i system load switch when v bus_ is invalid, or when the v sys_ load is greater than the input current limit. when a valid voltage is present at v bus_ , v sys_ is limited to 4.35v when using the max8895v/MAX8895X/ max8895y, and 4.53v when using the max8895w. when the system load current (i sys_ ) exceeds the v bus_ current limit v bat_ also powers v sys_ to maintain the load current. bypass v sys_ to dgnd with a 10 f f x5r or x7r ceramic capacitor. both sys_a and sys_b must be connected together externally. b4 sys_b sys_b sys_b a5 bus_a bus_a bus_a usb power input (v bus_ ). during initial connection of an external device, the max8895_ identifies the type of connection established and set the input current limit accordingly. bypass v bus_ to dgnd with a 10 f f x5r or x7r ceramic capacitor. both bus_a and bus_b must be connected together externally. b5 bus_b bus_b bus_b b1 idn idn idn charge termination current threshold. connect a resistor from idn to agnd to set the termination current threshold from 10ma to 160ma. i term = 2400/r idn if idn is connected to int_3v3, the termination current is set to the default i chg _ done threshold. downloaded from: http:///
14 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y pin description (continued) pin name function max8895w max8895v/ MAX8895X max8895y b2 ? chg chg active-low, charging indicator. chg is an open-drain output that is pulled low when the battery is in prequalification mode, fast-charge mode, or top-off states. otherwise, chg is high impedance. chg_type ? ? chg_type is used to indicate capacity of input current. if chg_type is high, the input current can be greater than or equal to 500ma. if chg_type is low, the input current is 100ma from the usb 2.0 host. c1 ? ? xin crystal oscillator input. connect xin to one side of a parallel resonant 12mhz 0.25% crystal and a capacitor to agnd. xin can also be driven by an external clock referenced to int_3v3. ? enu_en ? automatic enumeration enable. connect enu_en to agnd to allow the max8895v/MAX8895X to automatically perform enumeration. connect to int_3v3 or drive logic-high to force the input current limit to 100ma without performing an adapter type detection. enu_en ? ? automatic enumeration enable. connect enu_en to agnd to allow the max8895w to automatically perform enumeration. by connecting enu_en to int_3v3 or drive logic-high, disables automatic enumeration and sets the input current limit to level determined by the ibus_def if a usb 2.0 device is detected. c2 ? preq preq active-low, prequalification charging output. preq is an open-drain output that is pulled low when the charger enters the prequalification state. det_done ? ? active-low adapter-type detection done output. det_done is an open- drain output that is pulled low when adapter detection is completed. det_ done is high impedance in suspend mode. c3 uok uok uok active-low, v bus_ power-ok output. uok is an open-drain output that is pulled low when a valid input is detected at v bus_ . c4 kb_tm kb_tm kb_tm keyboard test mode. in normal operation, connect kb_tm to agnd. this input is only used during usb certification. c5 agnd agnd agnd analog ground. both agnd and dgnd should be connected together at the negative terminal of the battery. d1 ? ? xout crystal oscillator output. connect xout to one side of a parallel resonant 12mhz q 0.25% crystal and a capacitor to agnd. leave xout unconnected if xin is driven by an external clock. sus_en sus_en ? automatic suspend mode detection enable. connect sus_en to agnd to disable the automatic suspend mode detection. connect sus_en to int_3v3 or drive logic-high to enable the automatic detection of suspend mode. d2 ? rwu rwu remote wake-up. connect rwu to agnd or logic-low for remote wake-ups whenever the device is put into suspend mode and the supervisor determines that more current is needed. ibus_def ? ? sets usb input current if adapter is detected as a usb 2.0 device and enu_en is logic-high. if ibus_def is connected high, the input current limit is set to 500ma. if ibus_def is connected low or to ground, the input current limit is set to 100ma. downloaded from: http:///
15 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y pin description (continued) pin name function max8895w max8895v/ MAX8895X max8895y d3 cen cen cen charger enable input. connect cen to agnd to enable battery charging when a valid source is connected at v bus_ . connect cen to int_3v3 or drive logic-high to disable battery charging. in this condition the usb state machine is still active, and v sys_ is powered from v bus_ under normal conditions and supplemented from v bat_ if sufficient current is not available from v bus_ input. d4 flt flt flt active-low fault output. flt is an open-drain output that is pulled low when the battery charger timer expires before prequalification or fast-charge completes. flt is also pulled low during adapter type detection or if usb enumeration fails. d5 d+ d+ d+ usb d+ signal. connect d+ to a usb ?b? connector through a 33 i series resistor. the 1.5k i d+ pullup resistor is internal to the device (for max8895y only). e1 ct ct ct timer set capacitor. connect a capacitor from ct to agnd to set the fault timers for prequalification and fast-charge. t prequal = 16min x (c ct /0.068 f f) t fchg = 100min x (c ct /0.068 f f) t mtchg = 4min x (c ct /0.068 f f) if ct is connected directly to agnd, the default timers are used. e2 thm thm thm thermistor input. connect a negative temperature coefficient (ntc) thermistor that has good thermal contact with the battery from thm to agnd. connect a resistor equal to the thermistor at t a = +25 n c resistance from thm to int_3v3. charging is suspended when the thermistor is outside the hot and cold limits. connect thm to agnd to disable the thermistor temperature sensor. e3 int_3v3 int_3v3 int_3v3 ldo output. int_3v3 is the output of an ldo that powers the internal circuitry. int_3v3 is powered from the v bus_ input. connect a 0.1 f f capacitor from int_3v3 to agnd. e4 dgnd dgnd dgnd digital ground. both agnd and dgnd should be connected together at the negative terminal of the battery. e5 d- d- d- usb d- signal. connect d- to a usb ?b? connector through a 33 i series resistor. the 1.5k i d- pullup resistor is internal to the device (for max8895v/ max8895w/MAX8895X only). downloaded from: http:///
16 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 1. max8895v/MAX8895X block diagram li+ batter y charger an d sys load switch charge r current voltag e contro l v bus_ out of rang e v bus_ valid usb powe r management d+ bus_abus_b sys_asys_b set in pu t current limi t set in pu t current limi t ic thermal regulation i lim i lim - i sys i sys_ usb interface logi c po r i lim r tb r t r iset r idn c ct c int_3v3 3.3v for internalusb transceive r tosystem load i chg_max i chg usb adapter t ype detectio n an d enum eratio n uok r d+ d- d+ gnd d- v bus bat-ntc bat+ r d- support remote wake-up force re mote wake-up chargingte rminated chargingin progress prechargingte rminated prechargingin progress rwu automated suspend enabled automated suspend disabled sus_en bat_abat_b iset thm int_3v3 chg automatic enumeration disabled automatic enumeration enabled enu_en keyboard test mode enabled keyboard test mode disabled kb_tm forced standby mode automatic standby mode stdby int_3v3 no faultfault charger disabledcharger enabled dgnd agnd thermistor monitor charge termination and monitor charge timer max8895vMAX8895X flt cen ct preq idn downloaded from: http:///
17 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 2. differential input configuration li+ batter y charger an d sys load switch charge r current voltag e contro l v bus_ out of rang e v bus_ valid usb powe r management d+ bus_abus_b sys_asys_b in pu t current limi t set in pu t current limi t ic thermal regulation i lim i lim - i sys i sys_ usb interface logi c po r i lim r tb r iset r idn c ct c int_3v3 3.3v for internalusb transceive r tosystem load i chg_max i chg usb adapter t ype detectio n an d enum eratio n uok r d+ d- d+ gnd d- v bus bat-ntc bat+ r d- support remote wake-up force re mote wake-up chargingte rminated chargingin progress prechargingte rminated prechargingin progress rwu keyboard test mode enabled keyboard test mode disabled kb_tm bat_abat_b iset thm int_3v3 chg forced standby mode automatic standby mode stdby int_3v3 no faultfault charger disabledcharger enabled dgnd agnd thermistor monitor charge termination and monitor charge timer max8895y flt cen ct preq idn xinxout oscillator r t downloaded from: http:///
18 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 3. max8895w block diagram li+ battery charger and sys load switch charge r curren t voltag e contro l v bus_ out of rang e v bus_ valid usb powe r management d+ bus_abus_b sys_asys_b in pu t current limi t se t in pu t current limi t ic thermal regulation i lim i lim - i sys i sys_ usb interface logi c po r i lim r thm r iset r idn c int_3v3 3.3v for usb transceiver tosystem load i chg_max i chg u sb adapter t ype detectio n an d e num eratio n uok d- d+ gnd d- v bus bat-ntc bat+ bat_abat_b iset thm int_3v3 keyboard test mode enabled keyboard test mode disabled kb_tm forced standby mode automatic standby mode stdby int_3v3 no faultfault charger disabledcharger enabled thermistor monitor charge termination and monitor charge timer max8895w flt cen idn dgnd agnd sus_en automatic suspend enabled automatic suspend disabled enu_en automatic suspend enabled automatic suspend disabled adap te r detection in progress adapter detection complete det_done chg_type r 500ma input current limi t 100ma max. input current limi t ibus_def in pu t curre nt limit set to 500m a in pu t curre nt limit set to 100m a c timer ct downloaded from: http:///
19 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 4. max8895v/MAX8895X typical application circuit bus_a micro usb-b bus_b sys_asys_b r d+ d+ d- gnd v bus c bus c sys r d- rwu sus_en enu_en kb_tm stdby preq uok d+d- bat_abat_b thm int_3v3 iset c bat 1-cell li+ r tb c int_3v3 r iset r tp r ts c ct idn ct r idn cen chg flt dgnd agnd max8895vMAX8895X r t name value function c bus 10 f f, 16v decoupling of input supply. c sys 10 f f, 6.3v decoupling of system rail. c bat 10 f f, 6.3v decoupling of battery rail. r t user dependent thermistor for thermal sensing. see the thermistor input (thm) section for details. r tb , r tp , r ts user dependent bias resistors for thermal sensing. see the thermistor input (thm) section for details. c int_3v3 0.1 f f, 6.3v decoupling of internal 3.3v rail. c ct 1000pf to 0.2 f f capacitor to set charge timer, optional. see the fault output ( flt ) and charge timer (ct) section for details. r iset 1.875k i to 30k i resistor to set maximum charging current, optional. r idn 15k i to 240k i resistor to set termination current for charger, optional. r d+ , r d- 33 i d+/d- serial impedance. downloaded from: http:///
20 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 5. max8895y typical application circuit bus_a micro usb-b bus_b sys_asys_b r d+ d+ d- gnd v bus c bus c xtal_in c xtal_out xtal c sys r d- rwu kb_tm stdby d+d- thm int_3v3 iset r tb c int_3v3 r iset r tp r ts c ct idn ct r idn preq uok chg flt cen xin xout max8895y dgnd agnd bat_abat_b c bat 1-cell li+ r t name value function c bus 10 f f, 16v decoupling of input supply. c sys 10 f f, 6.3v decoupling of system rail. c bat 10 f f, 6.3v decoupling of battery rail. r t user dependent thermistor for thermal sensing. see the thermistor input (thm) section for details. r tb , r tp , r ts user dependent bias resistors for thermal sensing. see the thermistor input (thm) section for details. c int_3v3 0.1 f f, 6.3v decoupling of internal 3.3v rail. xtal 12mhz 2500ppm max8895y only, clock source for full-speed mode, requires a 2500ppm or better accuracy. c xtal_in user dependent max8895y only, crystal load capacitor, only required for full-speed operation. see the external crystal/ceramic resonator section for details. c xtal_out user dependent max8895y only, crystal load capacitor, only required for full-speed operation. c ct 1000pf to 0.2 f f capacitor to set charge timer, optional. see the fault output ( flt ) and charge timer (ct) section for details. r iset 1.875k i to 30k i resistor to set maximum charging current, optional. r idn 15k i to 240k i resistor to set termination current for charger, optional. r d+ , r d- 33 i d+/d- serial impedance. downloaded from: http:///
21 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 6. max8895w typical application circuit bus_a micro usb-b bus_b sys_asys_b r d+ d+ d- gnd v bus c bus c sys r d- det_done sus_en enu_en d+d- thm int_3v3 iset r tb c int_3v3 r iset r tp r ts c ct idn ct r idn uok flt kb_tm stdby cen chg_type ibus_def max8895w dgnd agnd bat_abat_b c bat 1-cell li+ r thm name value function c bus 10 f f, 16v decoupling of input supply. c sys 10 f f, 6.3v decoupling of system rail. c bat 10 f f, 6.3v decoupling of battery rail. r thm user dependent thermistor for thermal sensing. see the thermistor input (thm) section for details. r tb , r tp , r ts user dependent bias resistors for thermal sensing. see the thermistor input (thm) section for details. c int_3v3 0.1 f f, 6.3v decoupling of internal 3.3v rail. c ct 1000pf to 0.2 f f capacitor to set charge timer, optional. see the fault output ( flt ) and charge timer (ct) section for details. r iset 1.875k i to 30k i resistor to set maximum charging current, optional. r idn 15k i to 240k i resistor to set termination current for charger, optional. r d+ , r d- 33 i d+/d- serial impedance. downloaded from: http:///
22 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y detailed description the max8895_ is an integrated 1-cell li+ charger with usb enumeration capability. all power switches for charging and switching the load between battery and external power are internal. no external mosfets are required. the max8895_ makes it possible to negotiate more than 100ma of charging current from a usb host or hub without processor intervention. the max8895_ also auto - matically detects a dedicated charger or usb charger and set the input current limit accordingly. the battery charge current can be set up to 1.85a. input power not used by the system charges the battery. usb interface an integrated usb peripheral controller provides auto-enumeration for full-speed (max8895y) and low-speed (max8895v/max8895w/MAX8895X) modes. the usb controller executes the adapter detection sequence, which consists of detecting the type of adapter that is externally connected and setting the input current limit accordingly. if attached to a usb charger (host or hub) or a usb 2.0 (host or hub), it enumerates as an hid device and nego - tiates the maximum charging current level (from v bus_ ). the max8895v/max8895w/MAX8895X operate in low-speed mode, using an internal 6mhz oscillator, and does not require an external crystal to be usb compliant. the max8895y operates in full-speed mode and requires an external 12mhz crystal. according to the usb 2.0 specification, a low-speed device is not allowed to use a standard usb ?b? con - nector. this is why max8895_ is available in both a low- and full-speed version. this makes it possible to use a custom or captive cable for low-speed mode using the max8895v/max8895w/MAX8895X and still be usb compliant. operating in full-speed mode, using the max8895y allows use of a standard usb ?b? connector. d+ and d- the internal usb full speed (max8895y)/low-speed (max8895v/max8895w/MAX8895X) transceiver is brought out to the bidirectional data pins d+ and d-. these pins are esd protected up to q 8kv (hbm). connect these pins to a usb ?b? custom connector through external 33 i series resistors. the max8895v/ MAX8895X provide an automatic switchable 1.5k i pul - lup resistor for d-, while the max8895y provides an auto - matic switchable 1.5k i pullup resistor for d+. adapter detection when an adapter is present on v bus_ , the max8895_ examines the external device to identify the type of adapter connected. the possible adapter types are: u dedicated charger u usb charger (host or hub) u usb 2.0 (host or hub) low power u usb 2.0 (host or hub) high power each of these different devices has different current capability as shown in table 1. figure 7. usb rise and fall timing figure 8. load for d+/d- ac measurements table 1. adapter types usb timing t ri se t fall 90%10% max8895vmax8895w MAX8895X max8895y d+ or d- c l = 50pf 15k i test point 3.3 adapter type output voltage output current dedicated charger 4.75v to 5.25v at i load < 500ma 2.0v to 5.25v for i load r 500ma 500ma to 1.85a usb charger 4.75v to 5.25v at i load < 500ma 0 to 5.25v for i load r 500ma 500ma to 900ma for low speed, full speed 500ma to 1.5a for low speed and full speed usb 2.0 low power 4.25v to 5.25v 100ma (max) usb 2.0 high power 4.75v to 5.25v 500ma (max) downloaded from: http:///
23 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y when an adapter is connected to the max8895_, a series of tests is performed to identify the type of device connected. the sequence is done according to the flow charts in figures 7 and 8. figures 9, 10, and 11 show the adapter-type detection timing. figure 9. MAX8895X flow chart for adapter type detection figure 10. max8895v flow chart for adapter type detection disable v dp_src disable v dm_sink disable dm_pu disable i _dm_pd disable dp_cd_pu disable v dp_src disable v dm_sink enable i _dm_pd enable dp_cd_pu delay t dp_src_hc disable v dp_src disable v dm_sink i lim = i enu delay t dp_src_hc enable dm_pu enable v dp_src enable v dm_sink delay t dp_src_on debounce t usb_db usb_ok = high no nono yesyes yes disable v dp_src disable v dm_sink disable dm_pu disable i _dm_pd disable dp_cd_pu i lim = i sus stdby = high yes i lim = i usb_lp i lim = i dchg i lim = i usb_chg enu_en = high yes v dat_ref p v dm < v dm_ih no disable i _dp_pd disable dp_cd_pu enable dm_pu i lim = i uss_chg yes dm > v dm_ih no no no yes yes yes yes yes yes disable dm_pu i lim = i sus delay t fault enumeration succeeded no usb suspend? no sus_en = low no no no no usb host d- high to low transition usb_ok = low from any condition stdby = high from any condition, usb_ok = _high yes enumeration succeeded disable dp_pu i lim = i sus delay t fault ilim = usb_lp or usb_hp i lim = i sus delay t rwu initiate resume delay t re_enum yes charge done rwu supported by host rwu = low disable v dp_src disable v dm_sink disable dm_pu disable i _dm_pd disable dp_cd_pu disable v dp_src disable v dm_sink enable i _dm_pd enable dp_cd_pu delay t dp_src_hc disable v dp_src disable v dm_sink i lim = i enu delay t dp_src_hc enable dm_pu enable v dp_src enable v dm_sink delay t dp_src_on debounce t usb_db usb_ok = high no nono yesyes yes disable v dp_src disable v dm_sink disable dm_pu disable i _dm_pd disable dp_cd_pu i lim = i sus stdby = high yes i lim = i usb_lp i lim = i dchg i lim = i usb_chg enu_en = high yes v dat_ref p v dm < v dm_ih no disable i _dp_pd disable dp_cd_pu enable dm_pu i lim = i uss_chg yes dm > v dm_ih no no no yes yes yes yes yes no disable dm_pu i lim = i sus delay t fault enumeration succeeded no usb suspend? no sus_en = low no no yes no usb host d- high to low transition usb_ok = low from any condition stdby = high from any condition, usb_ok = _high yes enumeration succeeded disable dp_pu i lim = i sus delay t fault ilim = usb_lp or usb_hp i lim = i sus delay t rwu initiate resume delay t re_enum yes charge done rwu = low rwu supported by host downloaded from: http:///
24 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 11. max8895y flow chart for adapter type detection disable v dp_src disable v dm_sink disable dp_pu disable i _dm_pd disable dp_cd_pu disable v dp_src disable v dm_sink enable i _dm_pd enable dp_cdc_pu delay t dp_src_hc disable v dp_src disable v dm_sink i lim = i enu delay t dp_src_hc enable dp_pu enable v dp_src enable v dm_sink delay t dp_src_on debounce t usb_db usb_ok = high no nono yesyes yes disable v dp_src disable v dm_sink disable dp_pu disable i _dm_pd disable dp_cd_pu i lim = i sus stdby = high yes i lim = i usb_lp i lim = i dchq i lim = i usb_chg enu_en = high yes no disable i _dp_pd disable dp_cd_pu enable dp_pu i lim = i uss_chg yes dm > v dm_ih no no yesyes yes yes yes yes disable dp_pu i lim = i sus delay t fault enumeration succeeded no usb suspend? no no sus_en = low no no no no usb host d+ high to low transition usb_ok = low from any condition stdby = high from any condition, usb_ok = _high yes enumeration succeeded disable dp_pu i lim = i sus delay t fault ilim = usb_lp or usb_hp i lim = i sus delay t rwu initiate resume delay t re_enum yes charge done rwu supported by host rwu = low v dat_ref p v dm < v dm_ih downloaded from: http:///
25 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 12. max8895w flow chart for adapter type detection debounce t usb_db usb_ok = high no no yes yes yes disable v dp_src disable v dm_sink disable dm_pu disable i _dm_pd disable dp_cd_pu ilim = usb_lp or usb_hp stdby = high enable v dp_src enable v dm_sink delay t dp_src_on i lim = i dchg det_done = 0 ibus_def = 1 i lim = i usb_chg disable v dp_src disable v dm_sink i lim = i enu delay t dp_src_hc enable dp_pu disable v dp_src disable v dm_sink enable i _dm_pd enable dp_cdc_pu delay t dp_src_hc yes no yes dm > v dm_ih no no yes yes yes yes yes yes disable dm_pu i lim = i sus delay t fault enumeration succeeded no usb suspend? no no sus_en = low no no no usb host d+ high to low transition usb_ok = low from any condition stdby = high from any condition, usb_ok = _high yes enumeration succeeded disable dm_pu i lim = i sus delay t fault i lim = v ibus_def delay t rwu initiate resume yes charge done rwu supported by host? dm = v dat_ref disable i _dp_pd disable dp_cd_pu enable dm_pu i lim = i usb_chg det_done = 0 ibus_def = 1 enu_en = low det_done = 0 i lim = i sus det_done = 0 disable v dp_src disable v dm_sink disable dp_pu disable i _dm_pd disable dp_cd_pu i lim = i sus det done = 1 downloaded from: http:///
26 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y once the type of adapter is determined, the max8895_ determines the maximum input current limit, if the exter - nal adapter is recognized as a usb charger or usb 2.0 device. the max8895_ then initiates enumeration and determine the maximum input current limit according to figure 13. low-power mode driving stdby high disables the charger as well as v sys_ , to reduce the input current drawn from v bus_ . the current drawn in this mode is less than 500 f a for the max8895v/max8895w/MAX8895X and 2.5ma for the max8895y. in this mode, the d+ and d- lines become high impedance. when stdby is high, v sys_ is regulated to 50mv (typ) below v bat_ . usb suspend according to the usb rev 2.0 specification, when a usb host stops sending traffic for at least 10ms to a peripher - al (max8895_), the peripheral must enter a power-down state called suspend. once suspended, the peripheral must have enough of its internal logic active to recognize when the host resumes signaling, or if enabled, for gen - erating remote wake-up.the max8895_ enters suspend state in two ways: u max8895v/max8895w/MAX8895X: when no activi - ty is present on d+/d- for 10ms (max), the max8895v/max8895w/MAX8895X automatically enters sus - pend mode to be compliant with usb specification. the max8895v/max8895w/MAX8895X only enters suspend mode if sus_en is pulled high. when entering suspend mode the max8895v/max8895w/ MAX8895X disables the charger as well as v sys_ to reduce the input current drawn from v bus_ . the current drawn in this mode is less than 500 f a for the max8895v/max8895w/MAX8895X, ensuring that the device is compliant with usb specification. in sus - pend state the bus is idle: d+ is low and d- is kept high by the max8895v/max8895w/MAX8895X pul - lup resistor. when in suspend mode, v sys_ is pow - ered from v bat_ . when entering automatic suspend mode, the flt output is pulled low as an indication that the charger is disabled. u max8895y: when no activity is present on d+/d- for 10ms (max), the max8895y automatically enters suspend mode to be compliant with usb specifica - tion. when entering suspend mode, the max8895y disables the charger as well as v sys_ to reduce the input current drawn from v bus_ . the current drawn in this mode is less than 2.5ma, ensuring that the device is compliant with the usb specification. in suspend state, the bus is idle: d- is low and d+ is kept high by the max8895y pullup resistor. when in suspend mode, v sys_ is powered from v bat_ . when entering automatic suspend mode, the flt output is pulled low as an indication that the charger is disabled. figure 13. flow chart for enumeration process i lim = 500ma send connect enumeration initiated return to main loop no no yes yesyes yes ic is in configured status enum_500ma enum_100ma t < t enum delay t enu_fault disable dm_pu (max8895v/max8895w/ MAX8895X) dp_pu (max8895y) i lim = 100ma enable dm_pu (max8895v/max8895w/ MAX8895X) dp_pu (max8895y) ic is in configured status no yes t < t enum disable dm_pu delay t enu_fault downloaded from: http:///
27 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 14a. charger detection timing diagram (max8895v/MAX8895X) figure 14b. usb detection timing diagram (max8895v/MAX8895X) v bus_ v flt input current limi t charger (max8895vMAX8895X) 0ma v dp_src i dm_sink on off onon offoff logic-lo w logic-lo w logic-highlogic-high dm_pu d- 0.5ma dedica te d charger or usb charger usb charger dedica te d charge r usb charger dedica te d charge r 1500ma 1800ma t dp_src_hc t dp_src_on v bus_ v flt input current limi t usb 2.0 (max8895vMAX8895X) 0ma v dp_src i dm_sink on off onon offoff logic-lo w logic-lo w logic-highlogic-high dm_pu d- 0.5ma usb 2.0 low power usb 2.0 high power 100ma 500ma t dp_src_o n downloaded from: http:///
28 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 15a. charger detection timing diagram (max8895y)figure 15b. usb detection timing diagram (max8895y) v bus_ v flt input current limi t charger (max8895y) 0ma v dp_src i dm_sink on off onon offoff logic-lo w logic-lo w logic-highlogic-high dp_pu d- 0.5ma dedica te d charge r or usb charger usb charger dedica te d charger usb charge r dedica te d charger 1500ma 1800ma t dp_src_hc t dp_src_on v bus_ v flt input current limi t usb 2.0 (max8895y) 0ma v dp_src i dm_sink on off onon offoff logic-lo w logic-lo w logic-highlogic-high dp_pu d- 0.5ma usb 2.0 low powe r usb 2.0 high power 100ma 500ma t dp_src_on downloaded from: http:///
29 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 16a. charger detection timing diagram (max8895w)figure 16b. usb detection timing diagram (max8895w) v bus input current limi t 0ma v dp_src v dm_sink on off onon offoff logic-lo w logic-lo w logic-hig h logic-hig h logic-lo w logic-hig h dm_pu d- 0.5ma 1500ma 1800ma t dp_src_con t dp_src_on det_done ibus_def v bus input current limi t 0ma v dp_src v dm_sink on off onon offoff logic-lo w logic-lo w logic-hig h logic-hig h logic-lo w logic-hig h dm_pu d+ 0.5ma 100ma 500ma t dp_src_con t dp_src_on det_done ibus_def usb 2.0 low powe r usb 2.0 high power downloaded from: http:///
30 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y wake-up and usb resume the max8895_ can wake up four ways while in suspend mode: u logic-high to logic-low transition of stdby initiating enumeration. u max8895v/max8895w/MAX8895X: if stdby is logic-low and sus_en is logic-high, the max8895v/max8895w/MAX8895X monitor the bus activity on the d- line. if the host resumes bus activity, the max8895v/max8895w/MAX8895X detects this as a 1 to 0 transition on d- . once this occurs, the device restarts the oscillator and waits for it to stabilize. u max8895y: if stdby is logic-low, the max8895y monitors the bus activity on the d+ line. if the host resumes bus activity, the max8895y detects this as a 1 to 0 transition on d+ . once this occurs, the device restarts the oscillator and waits for it to stabilize. u remote wake-up is supported by the max8895v/ MAX8895X/max8895y, but the remote wake-up fea - ture must be enabled by the host during the enu - meration process. once suspended, the max8895v/ MAX8895X/max8895y look at the state of the battery charger. if the charger is not in the done state, the max8895v/MAX8895X/max8895y initiate a remote wake-up signal. if the charger is in the done state, a remote wake-up is not initiated before the charger is restarted due to a drop in battery voltage. u when the max8895v/MAX8895X/max8895y initiate a remote wake-up, they first restart the oscillator and wait for the oscillator to stabilize, and then send the remote wake-up event to signal to the host that it needs to be driven out of the suspend status. u if rwu is connected to ground and the remote wake-up feature has not been set by the host during enumeration, the ic waits t re_enum after entering suspend mode, then disconnects the pullup resistor and reinitiates the charger type detection. enumeration usb bus enumeration is an activity that identifies and assigns unique addresses to devices attached to the bus. once the max8895_ detects v bus_ is valid for t usb_db , the max8895_ initiates the detection process to determine the type of device that it is connected to. if the device type is a usb 2.0 host/hub or usb char - ger, a 1.5k i pullup resistor is connected between d- (max8895v/max8895w/MAX8895X) or d+ (max8895y) to int_3v3. enumeration is started on the max8895v/max8895w/ MAX8895X only if enu_en is logic-low. if enu_en is logic-high, the max8895v/max8895w/MAX8895X does not connect a pullup resistor between d- and int_3v3, and the current limit is set to 100ma regardless of the input type. when the usb 2.0 host/hub or usb charger detects a plugged-in peripheral (max8895_), it interrogates the peripheral to learn about its capabilities and require - ments; and if all is well, configures it to bring it on line. this process is known as enumeration. during enumeration the host sends multiple requests to the device (max8895_) asking for descriptors (see table 2) that define the device operation. all the enumeration tasks are self-managed by the max8895_ serial interface engine (sie) without any pro - cessor intervention.the sie supports the following features: u usb 2.0 low-speed (1.5mbps): the max8895v/ max8895w/MAX8895X pulls d- high to indicate to the host that it is a low-speed device u full-speed (12mbps) operation: the max8895y pulls d+ high to indicate to the host that it is a full-speed device u human interface device (hid) in the consumer page (max8895_ does not require any custom drivers) u 8 bytes end-point zero (control end point) u 1 byte end-point one (int-in end point) u usb suspend/resume support u remote wake-up capability at the end of enumeration (if successful), the device is ready to transfer data (if needed) and enabled to sink the negotiated current from v bus_ . figure 17 shows usb bus traffic as captured by a catc usb bus analyzer. the traces show a pc (host) enumerating the peripheral (max8895v/max8895w/ MAX8895X). notice that the ls field indicates the low-speed (1.5mbps) operation of the max8895v/ max8895w/MAX8895X. 1) the host uses the default control end-point ep0 (shown in the ?endp? boxes) to send a request to the device. the host initially sends requests to address 0 (shown in the addr boxes) to communicate with a device to which it has not yet assigned a unique address. downloaded from: http:///
31 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 17. usb bus traffic: max8895v/max8895w/MAX8895X enumeration transfer packet dir control brequest wvalue windex descriptors time time stamp addr endp 0 69 _ > get get_descriptor device type device descriptor 0 l s 0 0x0000 6.80ms time reset time stamp 52.919ms 00002.2722 1739 25.881ms 00002.2673 4787 brequest wvalue windex wlength time time stamp set_configuration new configuration 10 0x0000 18.999ms 00002.4161 4435 wvalue windex wlength time time stamp 0x0000 0 0x0000 3.000ms stall 0x08 d h_>d tp c r i 00002.4313 4403 brequest wvalue windex descriptors time time stamp get_descriptor brequest 0x0a device type device descriptor 0x0000 5.986ms 00002.4009 5299 brequest wvalue windex descriptors time time stamp get_descriptor device type device descriptor 0x0000 6.000ms 00002.3521 4587 brequest wvalue windex descriptors time time stamp get_descriptor configuration type, index o configuration descriptor 0x0000 5.000ms 00002.3569 4579 brequest wvalue windex descriptors time time stamp get_descriptor report_descriptor type report descriptor 0x0000 15.000ms 00002.4337 4395 brequest wvalue windex descriptors time time stamp get_descriptor configuration type, index o4 descriptors 0x0000 21.000ms 00002.3609 4563 brequest wvalue windex descriptors time time stamp get_descriptor configuration type, index o4 descriptors 0x0000 8.000ms 00002.4097 4451 brequest wvalue windex descriptors time time stamp get_descriptor string type, langid codes, requested lang supported language id 0x0000 5.000ms 00002.3777 4539 brequest wvalue windex descriptors time time stamp get_descriptor string type, index 1 usb charger language id 0x0409 8.000ms 00002.3817 4515 brequest wvalue windex descriptors time time stamp get_descriptor string type, index 1 usb charger language id 0x0409 11.013 ms 00002.3921 4491 brequest wvalue windex descriptors time time stamp get_descriptor string type, langid codes requested lang supported language id 0x0000 5.000ms 00002.3881 4499 brequest wvalue windex time time stamp set_address 0x0000 wlength 0 new address 3 46.999ms 00002.3145 4675 transfer control addr endp 1 set 0 l s 0 transfer control addr endp 2 get 0 l s 0 transfer control addr endp 3 get 0 l s 0 transfer control addr endp 4 get 0 l s 0 transfer control addr endp 5 get 0 l s 0 transfer control addr endp 6 get 0 l s 0 transfer control addr endp 7 get 0 l s 0 transfer control addr endp 8 get 0 l s 0 transfer control addr endp 9 get 0 l s 0 transfer control addr endp 10 get 0 l s 0 transfer control addr endp 11 get 0 l s 0 transfer control addr endp 12 set 0 l s 0 transfer control addr endp 13 set 0 l s 0 transfer control addr endp 14 get 0 l s 0 transfer interrupt addr endp 15 in 3 l s 1 bytes transferred time time stamp 1 8.009ms 00002.4457 4371 bytes transferred time time stamp 1 7.991ms 00002.4421 4899 bytes transferred time time stamp 1 8.000ms 00002.4585 4339 bytes transferred time time stamp 1 8.000ms 00002.4649 4323 bytes transferred time time stamp 1 8.009ms 00002.4713 4307 bytes transferred time time stamp 1 7.991ms 00002.4777 4843 transfer interrupt addr endp 16 in 3 l s 1 transfer interrupt addr endp 17 in 3 l s 1 transfer interrupt addr endp 18 in 3 l s 1 transfer interrupt addr endp 19 in 3 l s 1 transfer interrupt addr endp 20 in 3 l s 1 brequest wvalue windex descriptors time time stamp get_descriptor configuration type, index o configuration descriptor 0x0000 5.000ms 00002.4057 4459 downloaded from: http:///
32 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 18. usb bus traffic: max8895y enumeration transfer 1 f s transfer 1 f s transfer 2 f s transfer 3 f s transfer 4 f s transfer 5 f s transfer 6 f s transfer 7 f s transfer 8 f s transfer 9 f s transfer 10 f s transfer 11 f s transfer 12 f s transfer 13 f s transfer 14 f s transfer 15 f s transfer 16 f s transfer 17 f s transfer 18 f s transfer 19 f s control reset 26.370ms addr endp set 00 control addr endp set 00 control addr endp get 10 control addr endp get 10 control addr endp get 10 control addr endp get 10 control addr endp get 1 0 control addr endp get 1 0 control addr endp get 10 control addr endp get 1 0 control addr endp get 1 0 control addr endp get 1 0 control addr endp get 1 0 control addr set 1 0 control addr endp set 1 0 control addr endp get 1 0 interrupt addr endp in 11 interrupt addr endp in 1 1 interrupt addr endp in 1 1 interrupt addr endp in 11 brequest wvalue windex descript0rs time get_descriptor configuration type 4 descriptors 0x0000 8.000ms wvalue time new configuration 1 20.001ms brequest wvalue windex descriptors time get_descriptor brequest set_configuration string type, index 1 string: usb charger language id 0x0409 30.001ms descriptors time hidm report descriptor 16.001ms brequest wvalue windex descriptors time get_descriptor brequest get_descriptor device type wvalue device type device descriptor descriptors device descriptor 0x0000 windex 0x0000 idle 6627 6.000ms brequest wvalue windex descript0rs time get_descriptor configuration type configuration descriptor 0x0000 5.000ms brequest wvalue windex 0x0a 0x0000 0x0000 brequest wvalue windex descript0rs time get_descriptor configuration type 4 descriptors 0x0000 9.000ms brequest wvalue windex descript0rs time get_descriptor configuration type, index o configuration type, index o 0x0000 8.000ms brequest wvalue windex stall time get_descriptor descriptor type 0x06, index 0 0x78 0x0000 3.001ms stall time 0x78 3.000ms brequest wvalue windex descript0rs time get_descriptor string type. langid codes requested 0x0409 language id 0x0000 5.000ms brequest wvalue windex descript0rs time get_descriptor string type, langid codes requested 0x0409 language id 0x0000 5.001ms brequest wvalue windex descript0rs time get_descriptor string type, index 1 string: usb charger language id 0x0409 8.000ms brequest wvalue time set_address new address 14 7.002ms brequest wvalue windex get_descriptor descriptor type 0x22, index 0 0x0000 bytes transferre d time 1 32.001ms bytes transferred time 1 32.001ms bytes transferred time 1 32.001ms bytes transferred time 1 0ns brequest wvalue windex descript0rs time get_descriptor device type device descriptor 0x0000 6.001ms downloaded from: http:///
33 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y table 2. device descriptor 2) the host begins by sending a get_descriptor_device request (transfer 0 in figure 16). it does this to deter - mine the maxpacketsize of the device?s ep0 buffer (for the max8895v/MAX8895X, it is 8 bytes). the host then resets the device by issuing a bus reset (packet 69). 3) in transfer 1, the host assigns a unique address to the peripheral by using the set_address request. the assigned address depends on how many other usb devices are currently attached to the host. in this case, the address assigned to our periph - eral device (max8895v/MAX8895X) is 3. thereafter, the max8895v/MAX8895X respond only to requests directed to address 3. this address remains in force until the host does a bus reset or the device is dis - connected. notice that the peripheral address field (addr) in the bus trace changes from 0 to 3 after transfer 1. 4) in transfers 2 to 11, the host asks for various descrip - tors. the device fsm needs to determine from the eight setup bytes which descriptor to send, use this information to access one of several character arrays (roms) representing the descriptor arrays. 5) in transfer 12, the host requests the device to use the specified configuration (1) and the device enters the configured state. according to the usb 2.0 specification, a bus powered device can be either low power (it may draw no more than 100ma) or high power (it may draw no more than 500ma). all devices must default to low power. the transition to high power is under software control (running on the host side). it is the responsibility of software to ensure adequate power is available before allowing devices to consume high-power. the max8895_ initiates enumeration by asking for 500ma of current. if the max8895_ does not enter con - figured status before the t enum (10s, typ), it interprets this as an indication that the host is not able to support the requested current. the max8895_ disconnects the pullup resistor on d- (max8895v/MAX8895X)/d+ (max8895y), wait for t enu_fault , and then retry to enu - merate, but now as a low current device (100ma). if the max8895_ has still not reached the configured status after t enum , the max8895_ assumes that either the host is nonresponsive or a wrong adapter type is detected. in this case, the max8895_ disconnects the pullup resistor on d- (max8895v/max8895w/MAX8895X)/d+ (max8895y) and wait for t enu_fault + t fault before starting the adapter detection process again.figure 18 shows the usb traffic captured during the max8895y enumeration. notice the field fs indicates the full-speed (12mbps) operation of the max8895y. field length (bits) offset (bits) decoded hexvalue description blength 8 0 0x12 0x12 descriptor size is 18 bytes bdescriptortype 8 8 0x01 0x01 device descriptor type bcdusb 16 16 0x0200 0x0200 device compliant to the usb specification version 2.0 bdeviceclass 8 32 0x00 0x00 each interface specifies its own class information bdevicesubclass 8 40 0x00 0x00 each interface specifies its own subclass information bdeviceprotocol 8 48 0x00 0x00 no protocols the device basis bmaxpacketsize0 8 56 0x08 0x08 maximum packet size for end-point zero is 8 idvendor* 16 64 ? ? vendor id is 2922: maxim integrated products idproduct* 16 80 0x5346 0x5346 product id is 21318 bcddevice 16 96 0x1234 0x1234 the device release number is 1.00 imanufacturer 8 112 0x00 0x00 the device does not have the string descriptor describing the manufacturer iproduct 8 120 0x01 0x01 the product stringed descriptor index is 1 iserialnumber 8 128 0x00 0x00 the device does not have the string descriptor describing the serial number bnumconfigurations 8 136 0x01 0x01 the device has 1 possible configuration downloaded from: http:///
34 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y smart power selector the smart power selector seamlessly distributes power between the external v bus_ input, the battery (v bat_ ), and the system load (v sys_ ). see figure 19. the smart power selector basic functions are:u with both an external adapter and battery connected: a. when the system load requirements are less than the input current limit, the battery is charged with residual power from the input. b. when the system load requirements exceed the input current limit, the battery supplies supplemental current to the load. u when the battery is connected and there is no external power input, the system is powered from the battery. u when an external power input is connected and there is no battery, the system is powered from v bus_ . if the junction temperature starts to get too hot (+110 n c typ), the charging rate is reduced. if this is not sufficient to cool down the max8895_, the input current limit is then reduced. system load switch an internal 55m i (typ) mosfet connects v sys_ to v bat _ (q2, figure 19) when no voltage source is avail - able at v bus_ and v bat_ is above the battery uvlo threshold. when an external source is detected at v bus_ , this switch controls the charging of v bat_ and v sys_ is powered from the valid input source through the input current limiter.the v sys_ - v bat_ switch also prevents v sys_ from fall - ing below v bat_ when the system load exceeds the input current limit. if that should happen, v sys_ is allowed to drop to v bat_ . at this point, the v sys_ - v bat_ switch turns on so that the battery supplies additional i sys_ load current. if the system load continuously exceeds the input current limit, then the battery does not charge, even though external power is connected. this is not expected to occur in most cases, since high loads usually occur only in short peaks. during these peaks, battery energy is used, but at all other times the battery charges. input limiter the input limiter distributes power from the external adapter to the system load and battery charger. in addi - tion to the input limiter?s primary function of passing power to the system and charger, it performs several additional functions to optimize use of available power. u input voltage limiting: if the v bus_ input voltage is above the overvoltage threshold (v bus_ovp ), the max8895_ enters overvoltage lockout (ovl). ovl protects the max8895_ and downstream circuitry from high-voltage stress up to 16v at v bus_ . in ovl, v int_3v3 remains on, the input switch that sees overvoltage (q1, figure 19) opens, flt is pulled low, and uok , chg , det_done , and preq become high-impedance. in ovl, the charger turns off. the v bat_ - v sys_ switch (q2, figure 19) closes, allowing the battery to power v sys_ . v bus_ is also invalid if it is less than v bat_ , or less than the usb undervoltage threshold (v bus_uvlo_f ). with an invalid input volt - age, v sys_ connects to bat_ through a 55m i (typ) switch (q2, figure 19). u input overcurrent protection: the current at v bus_ is limited to prevent input overload. this current limit is automatically selected to match the capabilities of the adapter source, whether it is a 100ma or 500ma usb 2.0 source, or 500ma to 1.8a for a dedicated adap - tor or usb charger. when the load exceeds the input current limit, v sys_ drops to 50mv (typ) below v bat_ and the battery supplies supplemental load current. * contact factory for specific vendor id and product id. figure 19. smart power selector block diagram figure 20. v sys_ regulation v bus_ v bat_ charge current q2 charge and sys load switch loadcurrent gnd q1 v sys_ system load system load 1-cell li+ max8895v max8895w MAX8895Xmax8895y 3.4v (min) time 140mv v bat_ v sys_ downloaded from: http:///
35 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 21. adaptive input current-limit regulation loop u thermal limiting: the max8895v/MAX8895X/ max8895y reduce input current by 5%/ n c when its die temperature exceeds t die_lim (+110 n c typ). the system load (v sys_ ) has priority over charger cur - rent, so the input current is first reduced by lowering the charge current. if the junction temperature still reaches t die_lim +20 n c in spite of charge current reduction, no input v bus_ current is drawn, the bat - tery supplies the entire system load, and v sys is regulated at 50mv (typ) below v bat_ . note: the on-chip thermal limiting circuitry is not related to, and operates independently from, the thermistor input. u adaptive battery charging: while the system is powered from v bus_ , the charger draws power from v sys_ to charge the battery. if the combined load between the charger and system exceeds the input current limit, an adaptive charger control loop reduces charge current to prevent the v sys_ voltage from col - lapsing. regulation threshold the max8895_ always regulates v sys_ to 140mv (typ) above v bat_ with a minimum voltage of 3.4v regardless of what device is connected. the 3.4v minimum voltage regulation reduces the ripple on v sys _ during peak load conditions where the input current limit is tripped. input current limit if the connected adapter is a usb 2.0 device the input current limit is set by default to 100ma. if enu_en is connected to int_3v3 or driven logic-high for the max8895v/MAX8895X/max8895y, the charger input current limit remains at 100ma. if enu_en is set to logic-high for the max8895w the charger?s input current limit is determined by the logic state of ibus_def. when enu_en is connected to agnd, automatic enu - meration is initiated. the max8895_ proceeds to deter - mine if the external usb device is a low- or high-power device and set the input current limit to 100ma or 500ma, respectively. for a dedicated charger or usb charger, the current limit is determined by loading the adapter. when the adapter?s output voltage starts to collapse, it is an indication that the current limit of the device is reached. the max8895_ set the input current limit to regulate v bus to v sys +440mv (typ). this ensures that the power dissipation in the max8895_ is kept to a minimum, and at the same time, ensuring that the adapter?s current capability is fully utilized. when a dedicated charger is detected, the input current limited is limited by the adap - tive input current limit. in this mode, it is up to the adapter to limit the maximum current, which is 1.85a for a dedi - cated charger and 1.5a for a usb charger, according to the usb charging specification. time i iilm 500ma 3.4v (min) adapter type detection adaptive input current-limit regulation 440mv (typ) 140mv (typ) v bus_ v bat_ v sys_ downloaded from: http:///
36 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y if the adapter output (v bus ) starts to drop below v sys - 440mv (typ), the input current limit function adap - tively decreases the input current limit to ensure that the adapter is not overloaded. when the input current limit is reached, the first action taken by the max8895_ is to reduce battery charge current. if, after the charge cur - rent is reduced to 0ma, the load at i sys still exceeds the input current limit, v sys begins to fall. when v sys drops to 50mv below v bat , the v sys - v bat switch turns on, using battery power to support the system load during the load peak. see figure 21 for more information. power monitor output ( uok ) uok is an open-drain output that pulls low when the v bus_ input has valid power. the uok monitor has several different thresholds, depending on what type of adapter detected. the differ - ent thresholds are as follows: u the initial detection threshold allows all types of adapters to be detected on v bus_ . once the type of adapter is determined, the uvlo threshold is changed. u for any usb 2.0 device the uvlo thresholds are set to be compliant with usb specifications. u for a dedicated charger, the uvlo (falling) threshold is lowered to v sys_ + 50mv (typ) to allow for support - ing collapsing charger types, allowing the max8895_ to operate with lower power dissipation. note that since the v bus_ uvlo threshold is changed after initial detection of the device type, there are condi - tions where the max8895_ can toggle between v bus_ valid and not valid. this is an indication that the adapter is not within the specified limits. see table 3 for more information. table 3. uok monitor thresholds figure 22. charging states time top-off maintenance charge precharg e t < t pchg t < t fchg t = t mtchg fast-charge charge don e i pchg i fchg 0.6 x i fchg i chg_done v chg_reg v bat_fchg_r v bat_pchg_r thresholds uvlo ovlo (v) initial v bus_ detection 4.0v (typ), rising 6.9 for usb 2.0 low power 3.9v (typ), falling for usb 2.0 high power 4.1v (typ), falling for dedicated charger to usb charger v sys_ + 50mv (typ), falling downloaded from: http:///
37 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y figure 23. charger flow chart soft-start to prevent input transients that can cause instability in the usb power source, the rate of change of input cur - rent and charge current is limited. when a valid usb 2.0 input is connected, the input current limit is ramped from 0 to 100ma in 50 f s. once enumeration is ended, the cur - rent can be ramped to 500ma or to the new input current limit value in 50 f s. when the charger is enabled, the charge current ramps from zero to the final value in 1.5ms (typ). charge cur - rent also ramps when transitioning to fast-charge from prequalification and when changing the usb charge current from 100ma to 500ma. note: there is no di/dt limiting if i iset is changed sud - denly using a switch at r iset . battery charger the battery charger has five different states of operation ( see figures 22 and 23) : u precharge: when the battery voltage is below v bat_pchg_r . in this state, the battery is charged at maximum i pchg . if the i pchg > i lim , then the precharging current is determined by the i lim (input current limit). charging a li+ battery at high charging current when it is fully discharged can cause the bat - tery to become unstable and potentially dangerous. charging at high charging rates on a fully discharged battery can also reduce life cycles of the li+ battery. u fast-charge: in fast-charge mode, the charging cur - rent is set to maximum i fchg . the actual charging current is determined by i lim - i sys_ . u top-off charge: in top-off mode, the battery voltage has almost reached the set point (v bat_fchg_r ). the charging current is reduced in this mode to prevent overcharging the battery, and also to minimize the power dissipation in the battery. u maintenance charge: the charger enters this mode when the charging current has dropped below the i chg_done threshold. the charger continues to charge for t mtchg time to ensure the battery is fully charged before the charger is disabled. u charge done: charger is disabled and only en- gages again if the battery voltage drops below the v bat_rechg threshold. uok = high-z (chg = high-z) flt = high-z i chg = 0ma ( ) max8895v/MAX8895X/ max8895y only no valid v bus v bus_uvlo > v bus_ or v bus_ovp < v bus_ from any state cen = highfrom any state v bus_uvlo < v bus_ < v bus_ovp t chg_timer > t pchg t chg_timer > t fchg t chg_timer > t fchg t chg_timer > t mtchg t thm_cold > t a or t thm_hot < t a t thm_cold < t a < t thm_hot uok = low (chg = high-z) flt = low i chg = 0ma charger off prequal uok = low preq = low (chg = low) flt = high-z i chg = i pchg uok = low (chg = low) flt = high-z *i chg = i fchg fast-charge fault uok = low (chg = high-z) flt = low i chg = 0ma top-off charge uok = low (chg = low) flt = high-z i chg = i fchg /2 uok = low (chg = high-z) flt = high-z i chg < i chg_done done uok = low (chg = high-z) flt = high-z i chg = 0ma temperature suspense uok = low (chg = high-z) flt = high-z i chg = 0ma charge timer paused cen = lowreset charge timer v bat_ > v bat_pchg_r reset charge timer v bat_ < v bat_pchg_f reset charge timer i chg < i chg_done and i bus < i lim t die < t die_lim reset charge timer i chg r i chg_done reset charge timer v bat_ < v bat_pchg_f reset charge timer from any charging state *charge timerslowed down by x2 if: i chg < i fchg /2 and paused if:i chg < i fchg /5 v bat_ > v bat_fchg_r v bat_ < v bat_fchg_f v bat_ > v bat_rechg reset charge timer maintenance charge downloaded from: http:///
38 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y charge enable ( cen ) when cen is logic-low, the battery charger is enabled. when cen is logic-high, the battery charger is disabled. cen does not affect v sys_ . in many systems, there is no need for the system controller (typically a micro - processor) to disable the battery charger because the max8895_ smart power selector circuitry independently manages charging and usb-battery power handover. in these situations, cen may be connected to ground. setting charge current (iset) iset adjusts the charge current to match the capacity of the battery. the maximum charging current can be fixed by connecting iset to int_3v3 or can be adjusted by connecting iset to ground through a resistor. when iset is connected to ground through a resistor the maximum charging current is determined using the following for - mula: fchg iset 3000 i r = where r iset is a resistor from iset to ground. determine the i fchg value by considering the charac - teristics of the battery. it is not necessary to limit charge current based on the capabilities of the expected adapt - er input, the system load, or thermal limitations of the pcb. the max8895_ automatically adjusts the charging algorithm to accommodate these factors. monitoring charge current (iset) in addition to setting charge current, iset can also be used to monitor the actual current charging the battery. the iset output voltage is: iset chg iset v i 2000 r ?? = ???? where:i chg is the actual battery charge current, r iset is a resistor from iset to ground.a 1.5v output indicates the battery is being charged at the maximum fast-charge current (i fchg ). 0v indi - cates no charging. the iset voltage is also used by the charger control circuitry to set and monitor the battery current. avoid adding more than 10pf of capacitance directly to the iset pin. if filtering of the charge current monitor is necessary, add a resistor of 100k i or more between iset and the filter capacitor to preserve char - ger stability.if the maximum charge current (i fchg ), is set to the default value, the current monitor function is not available. charge termination (idn) when the charge current falls to the termination thresh - old and the charger is in voltage mode, charging is com - plete. charging continues for a time period defined by the t chg_done and then enters the done state where charging stops.the idn input adjusts the charge current termination threshold. the termination threshold can be fixed by connecting idn to int_3v3 or can be adjusted by con - necting idn to ground through a resistor. when idn is connected to ground through a resistor, the charge done threshold is determined using the following formula: term idn 2400 i r = where r idn is a resistor from idn to ground. note that if charge current falls to i term as a result of the input or thermal limiter, the charger does not enter the done state. for the charger to enter done, charge current must be less than i term , the charger must be in voltage mode, and the input or thermal limiter must not be reducing charge current. the charger exits the done state and fast-charge resumes if the battery volt - age subsequently drops below v bat_rechg or if cen is cycled. connecting idn to int_3v3 selects the default termination current threshold. figure 24. monitoring charge current with the iset voltage charge discharg e monitoring the battery charge current using v iset 1.5v 0v 0a battery charge current (a) or = i fchg 1.5v r iset = x 2000 v iset (v) downloaded from: http:///
39 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y charge status outputs charge output ( chg ) (max8895v/MAX8895X/ max8895y only) chg is an active-low, open-drain output that is driven low during charging. chg is logic-low when the battery charger is in fast-charge and top-off states. when charge current falls to the charge termination threshold and the charger is in voltage mode chg goes high impedance. chg holds its current state if the thermistor causes the charger to enter temperature suspend mode. when the max8895v/MAX8895X/max8895y are used with a microprocessor, connect a pullup resistor between chg and the logic i/o voltage to indicate charge status to the microprocessor . alternatively, chg can sink up to 20ma for an led indicator. prequalification output ( preq ) (max8895v/MAX8895X/max8895y only) preq is an active-low, open-drain output that is driven low when the charger is in prequalification state. when the max8895v/MAX8895X/max8895y are used in con - junction with a microprocessor, connect a pullup resis - tor between preq and the logic i/o voltage to indicate charge status to the microprocessor. alternatively, preq can sink up to 20ma for an led indicator. fault output ( flt ) and charge timer (ct) flt is an active-low, open-drain output that is driven low during a battery fault. the fault state occurs when either the prequalification or fast-charge timer expires. the prequalification and fast-charge fault timers are set by c ct : ct prequal c t 16min 0.068 f = f ct fchg c t 100min 0.068 f = f while in fast-charge mode, a large system load or device self-heating may cause the max8895_ to reduce charge current. under these circumstances, the fast-charge timer adjusts to ensure that adequate charge time is still allowed. consequently, the fast-charge timer is slowed by 2x if charge current is reduced below 50% of the pro - grammed fast charge level. if charge current is reduced to below 20% of the programmed level, the fast-charge timer is paused. the fast-charge timer is not adjusted if the charger is in voltage mode where charge current reduces due to current tapering under normal charging. to exit a fault state, toggle cen or remove and recon - nect the v bus_ input source. note: a thermistor out-of- range or on-chip thermal limit conditions are not consid - ered faults. when the max8895v/MAX8895X/max8895y are used in conjunction with a microprocessor, connect a pullup resistor between flt and the logic i/o voltage to indicate fault status to the microprocessor . alternatively, flt can sink up to 20ma for an led indicator. chg_type output (max8895w only) the output chg_type is used to indicate the type of interface detected. if chg_type output is logic level low the input current limit is set to 100ma or less. if chg_type output is logic level high the input current limit is set to 500ma or greater. det_done output (max8895w only) det_done is an active low, open-drain output that is driven low once adapter detection is complete. det_done is high impedance in suspend mode. ibus_def output (max8895w only) the ibus_def input is only valid when enu_en is set to logic-high activating the adapter type detection. if the adapter type is detected as a usb 2.0 device, the input current limit is set to the programmed value and the max8895w does not initiate usb enumeration. if ibus_def is connected to ground or logic level low, the input current limit is set to 100ma. if ibus_def is con - nected to int_3v3 or logic level high, the input current limit is set to 500ma. thermistor input (thm) the thm input connects to an external negative tem - perature coefficient (ntc) thermistor to monitor battery or system temperature. charging is suspended when the thermistor temperature is out of range. the charge timers are suspended and hold their state, but no fault is indicated. when the thermistor comes back into range, charging resumes and the charge timer continues from where it was at previously. connecting thm to agnd disables the thermistor monitoring function. since the thermistor monitoring circuit employs an exter - nal bias resistor from thm to v int_3v3 (r tb , figure 25), the thermistor is not limited only to 10k i (at t a = +25 n c). any resistance thermistor can be used as long as the value of r tb is equivalent to the thermistor?s t a = +25 n c resistance. for example, with a 10k i at t a = +25 n c thermistor, use 10k i at r tb , and with a 100k i at t a = +25 n c thermistor, use 100k i . for a typical 10k i at t a = +25 n c thermistor and a 10k i r tb resistor, the charger enters a temperature suspend state when the thermistor resistance falls below 3.97k i (too hot) or rises above 28.7k i (too cold). these limits downloaded from: http:///
40 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y correspond to a 0 n c to +50 n c range when using a 10k i ntc thermistor with a beta of 3500. the general relation of thermistor resistance to temperature is defined by the following equation: 11 t 273 298 t 25 rr e ?? ?? ? ?? ?? + ?? ?? = where: r t = the resistance ( i ) of the thermistor at temperature t in n c. r 25 = the resistance ( i ) of the thermistor at t a = +25 n c. a = the material constant of the thermistor which typi- cally ranges from 3000k to 5000k.t = the temperature of the thermistor in n c. table 4 shows the max8895_ thm temperature limits for different thermistor material constants. figure 25. thermistor monitor circuitry table 4. fault temperatures for different thermistors max8895vMAX8895X max8895y all comparator s 60mv hysteresis cold thermistor circuitry cen thm agnd 0.74 xv int_3v3 0.28 xv int_3v3 0.03 xv int_3v3 hotenable thm thm out ofrange disable charger alternate thermistor connectio n r tb r t r t r ts r tp thermistor ? (k) 3000 3250 3500 3750 4250 r tb (k i ) (figure 22) 10 10 10 10 10 resistance at +25 n c (k i ) 10 10 10 10 10 resistance at +50 n c (k i ) 4.59 4.30 4.03 3.78 3316 resistance at 0 n c (k i ) 25.14 27.15 29.32 31.66 36.91 nominal hot trip temperature ( n c) 55 53 50 49 46 nominal cold trip temperature ( n c) -3 -1 0 2 4.5 downloaded from: http:///
41 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y some designs may require other thermistor temperature limits. the threshold adjustment can be accommodated by changing r tb , connecting a resistor in series and/or in parallel with the thermistor, or using a thermistor with different a . for example, a t a = +45 n c hot threshold and t a = 0 n c cold threshold can be realized by using a thermistor with a a of 4250 and connecting a 120k i resistor in parallel. since the thermistor resistance near t a = 0 n c is much higher than it is near t a = +50 n c, a large parallel resistance lowers the cold threshold, while only slightly lowering the hot threshold. conversely, a small-series resistance raises the cold threshold, while only slightly raising the hot threshold. raising r tb low - ers both the hot and cold thresholds, while lowering r tb raises both thresholds. thermal shutdown thermal shutdown limits total power dissipation in the max8895_. when the junction temperature exceeds +160 n c (typ), the device turns off, allowing the max8895_ to cool. the max8895_ turn on and begin soft-start after the junction temperature cools by 20 n c (typ). this results in a pulsed charge current during continuous thermal-overload conditions. external clock (max8895y) the max8895y includes full-speed usb 2.0 compat - ibility. usb 2.0 full speed requires that the system clock of the transceiver is within q 2500ppm, over temperature, aging, etc. therefore, the max8895y requires an exter - nal resonator or clock source to stay within this limit.the max8895y local oscillator and internal digital clocks are derived from the reference clock at the xin input. external crystal/ceramic resonator (max8895y) xin and xout are used to interface to an external 12mhz crystal or ceramic resonator. connect a 33pf load capacitor from both xin/xout to ground. requirements for the external resonator/crystal for max8895y: frequency: 12mhz q 0.25% c load : 33pf q 20% drive level: 200 f w series resonance resistance: 60 i (maximum), 30 i (typical) note: series resonance resistance is the resistance observed when the resonator is in the series resonant condition. this is a parameter often stated by quartz crys - tal vendors and is called r1. when a resonator is used in the parallel resonant mode with an external load capaci - tance, as is the case with the max8895y oscillator circuit, the effective resistance is sometimes stated. the effective resistance at the loaded frequency of oscillation is: 2 o eff load c r r1 1 c ?? ?? = + ?? ?? ?? ?? ?? where: r1 = series resonance resistance c o = crystal capacitor c load = external load capacitance for typical c o and c load values, the effective resis - tance can be greater than r1 by a factor of 2. external clock (max8895y) the max8895y can also be driven from an external clock. the max8895y accepts an external clock input at xin. the external clock can either be a digital level square wave or sinusoidal and this may be directly coupled to xin without the need for additional components. if the peaks of the reference clock are above v int_3v3 or below ground, the clock signal must be driven through a dc-blocking capacitor (approximately 33pf) connected to xin. the external clock source can either be enabled using the uok or int_3v3 signals depending on if the clock source is active-low or active-high enabled.if the int_3v3 rail is used, ensure that no significant load is taken from this output since this affects the perfor - mance of the max8895y. clock timing accuracy (max8895y) usb 2.0 specification requires the system clock to be within q 2500ppm over temperature, aging, etc. it is recommended to use a clock source with tighter initial accuracy to ensure that over time the accuracy of q 2500ppm is still valid. esd protection d+, d-, and v bus_ possess extra protection against static electricity to protect the devices up to q 8kv (hbm). the esd structures withstand high esd in all operating modes: normal operation, suspend mode, and powered down. v bus_ requires 1 f f ceramic capacitors connect - ed to ground as close as possible to the pins. downloaded from: http:///
42 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y esd test conditions esd performance depends on a variety of conditions. contact maxim for a reliability report that documents test setup, test methodology, and test results. figure 26 shows the human body model, and figure 27 shows the current waveform generated when discharged into a low impedance. this model consists of a 100pf capaci - tor charged to the esd voltage of interest, which then discharges into the test device through a 1.5k i resistor. applications information capacitor selection ceramic x5r or x7r dielectric capacitors are recommend - ed for best operation. when selecting ceramic capacitors in the smallest available case size for a given value, ensure that the capacitance does not degrade significantly with dc bias. generally, ceramic capacitors with high values and very small case size have poor dc bias characteris - tics. evaluate capacitors carefully before using. ground connections minimize trace lengths between the bypass capacitors and ground. use separate digital/power ground (dgnd) and analog ground (agnd) copper areas, and connect them together at the negative terminal of the battery. the pins and/or external components for kb_tm, crystal load capacitors, iset, idn, ct, thermistor, and int_3v3 should connect to a quiet analog ground. all other ground connections should connect to dgnd. recommended pcb layout and routing place all bypass capacitors for int_3v3, v bus_ , v bat_ , and v sys_ as close as possible to the device. connect the battery to bat_a and bat_b as close as possible to the device to provide accurate battery voltage sensing. make all high-current traces short and wide to minimize voltage drops. when using the max8895y, place the external crystal and load capacitors as close as possible to the max8895y. the crystal and load capacitors should be kept as far away as possible from the d+/d- traces. refer to the max8895 evaluation kit for an exam - ple layout. the max8895 evaluation kit supports the max8895v/MAX8895X and max8895y. figure 26. human body test model figure 27. human body model current waveform charge-current limit resistor discharge resistance storagecapacitor c s 100pf r d 1.5k i device under test high- voltage dc source 36.8% time current waveform peak-to-peak ringing(not drawn to scale) i r t rl t dl i p 100% 90% 10% 0 0 amperes downloaded from: http:///
43 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y chip information process: bicmos typical operating circuit note: all devices are specified over the -40c to +85c oper - ating temperature range. + denotes a lead(pb)-free/rohs-compliant package. t = tape and reel. ** contact factory for availability. ordering information v bus_ d+ d- bat_a/ bat_b charge andsystem load switch sys_ system load system load 1-cellli+ max8895v max8895w MAX8895Xmax8895y bus_ control logic usb interface oscillator part usb interface type pin-package max8895v ewa+t low speed 25 wlp 2.36mm x 2.36mm max8895w ewa+t** low speed 25 wlp 2.36mm x 2.36mm MAX8895X ewa+t low speed 25 wlp 2.36mm x 2.36mm max8895y ewa+t full speed 25 wlp 2.36mm x 2.36mm downloaded from: http:///
44 maxim integrated li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages . note that a ?+?, ?#?, or ?-? in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. package type package code outline no. land pattern no. 25 wlp w252d2+1 21-0453 refer to applications note 1891 e d aaaa pin 1 indicator marking a3 a2 a1 a see note 7 0.05 s s e b e1 d1 se sd 0.05 m s ab b a side view a top view bottom view a 1 package outline 25 bumps, wlp pkg. 0.4mm pitch 21-0453 d 0.64 0.19 0.45 0.025 0.27 1.60 1.60 0.40 0.00 0.00 w252d2+1 2.41 2.44 2.41 2.44 2.25 2.32 2.02 2.36 2.44 2.16 2.25 2.22 2.02 2.36 2.34 2.16 w252f2+1 e c d b 1 53 42 w252g2+1 w252h2+1 title document control no. rev. 1 1 approval common dimensions a a2 a1 a3 b e1 d1 e sd se 0.05 0.03 0.03 basic ref basic min max max min e d pkg. code depopulated bumps none notes: 1. terminal pitch is defined by terminal center to center value. 2. outer dimension is defined by center lines between scribe lines. 3. all dimensions in millimeter. 4. marking shown is for package orientation reference only. 5. tolerance is 0.02 unless specified otherwise. 6. all dimensions apply to pbfree (+) package codes only.7. front - side finish can be either black or clear. basicbasic - drawing not to scale - none nonenone downloaded from: http:///
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated 160 rio robles, san jose, ca 95134 usa 1-408-601-1000 45 ? 2012 maxim integrated the maxim logo and maxim integrated are trademarks of maxim integrated products, inc. li-ion chargers with smart power selector, adapter type detection, and usb enumeration max8895v/max8895w/MAX8895X/max8895y revision history revision number revision date description pages changed 0 7/10 initial release ? 1 10/10 added max8895w to data sheet 1?38 2 2/11 added patent information 1 3 4/11 added contact factory note for max8895w 1 4 9/12 added max8895v to data sheet 1?42 downloaded from: http:///

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