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general description the max8671x integrated power-management ic (pmic) is ideal for use in portable media players and other handheld devices. in addition to five regulated output voltages, the max8671x integrates a 1-cell lithi- um ion (li+) or lithium polymer (li-poly) charger and smart power selector with dual (ac-to-dc adapter and usb) power inputs. the dual-input smart power selector supports end products with dual or single power connectors. all power switches for charging and switching the system load between battery and external power are included on-chip. no external mosfets are required. maxim? smart power selector makes the best use of limited usb or ac-to-dc adapter power. battery charge current and input current limit are independent- ly set. input power not used by the system charges the battery. charge current and dc current limit are pro- grammable up to 1a while usb input current can be set to 100ma or 500ma. automatic input selection switches the system load from battery to external power. other features include overvoltage protection, charge status and fault outputs, power-ok monitors, charge timer, and battery thermistor monitor. in addition, on-chip thermal limiting reduces battery charge rate to prevent charger overheating. the max8671x offers adjustable voltages for all out- puts. similar parts with factory-preset output voltages are also available (contact factory for availability). applications portable audio players gps portable navigators features ? 16v-tolerant usb and dc inputs ? automatically powers from external power or battery ? operates with no battery present ? single-cell li+/li-poly charger ? three 2mhz step-down regulators up to 96% efficiency ? two low i q linear regulators ? output power-up sequencing ? thermal-overload protection max8671x pmic with integrated charger and smart power selector for handheld devices ________________________________________________________________ maxim integrated products 1 19-0885; rev 0; 8/07 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim's website at www.maxim-ic.com. evaluation kit available ordering information out4 0.6v to v sys 180ma out3 1v to v sys 425ma out2 1v to v sys 425ma out1 1v to v sys 425ma ac-to-dc adapter usb out1 out2 out3 out4 out5 sys dc usb en on off p pen1 pen2 usus cen cst1 cst2 dok uok li+/lipo battery pwm out5 0.6v to v sys 180ma max8671x + simplified applications circuit part temp range pin-package pkg code max8671xetl+ -40? to +85? 40 thin qfn-ep* 5mm x 5mm t4055-1 smart power selector is a trademark of maxim integrated products, inc. + denotes a lead-free package. * ep = exposed paddle.
max8671x pmic with integrated charger and smart power selector for handheld devices 2 _______________________________________________________________________________________ table of contents general description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 simplified applications circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 table of contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 smart power selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 system load switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 usb power input (usb) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 usb power-ok output ( uok ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 usb suspend (usus) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 dc power input (dc) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 dc power-ok output ( dok) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 battery charger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 battery regulation voltage (bvset) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 charge enable input ( cen ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 charge status outputs (cst1, cst2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 charge timer (ct) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 setting the charger currents (ciset) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 step-down converters (reg1, reg2, reg3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 pwm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 step-down dropout and minimum duty cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 step-down input capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 step-down output capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 step-down inductor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 step-down converter output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 linear regulators (reg4, reg5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 vl linear regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 enable/disable (en) and sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 soft-start/inrush current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 active discharge in shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 undervoltage and overvoltage lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 usb/dc uvlo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 usb/dc ovlo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 sys uvlo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 reg4/reg5 uvlo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 thermal limiting and overload protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 smart power selector thermal-overload protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 regulator thermal-overload shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 battery charger thermistor input (thm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 pcb layout and routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 package marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 chip information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
max8671x pmic with integrated charger and smart power selector for handheld devices _______________________________________________________________________________________ 3 table of contents (continued) tables table 1. input limiter control logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 table 2. dc current limit for standard values of r diset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 table 3. charge status outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 table 4. charge times vs. c ct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 table 5. ideal charge currents vs. charge setting resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 table 6. suggested inductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 table 7. 5mm x 5mm x 0.8mm thin qfn thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 table 8. trip temperatures for different thermistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 figures figure 1. max8671x typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 figure 2. functional diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 figure 3. usb power-ok logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 figure 4. programming dc current limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 figure 5. dc power-ok logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 figure 6. li+/li-poly charge profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 figure 7. charger state diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 figure 8. programming charge current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 figure 9. monitoring the battery charge current with the voltage from ciset to agnd . . . . . . . . . . . . . . . . . . 32 figure 10. step-down converter maximum output current example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 figure 11. enable/disable logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 figure 12. enable and disable waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 figure 13. reg5 disable detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 figure 14. thermistor input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 figure 15. package marking example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
max8671x pmic with integrated charger and smart power selector for handheld devices 4 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. usb, dc, pen1 to agnd.......................................-0.3v to +16v sys, bat, pv1, pv2, pv3 to agnd..........................-0.3v to +6v pg1, pg2, pg3, agnd .........................................-0.3v to +0.3v pv1, pv2, pv3 to sys............................................-0.3v to +0.3v vl to agnd ...........................................................-0.3v to +4.0v ciset, diset, bvset, ct, thm to agnd..-0.3v to (v vl + 0.3v) pv4, pv5, bp, fb1, fb2, fb3 to agnd ....-0.3v to (v sys + 0.3v) pen2, usus, cen , en, pwm to agnd ..................-0.3v to +6v cst1, cst2, dok , uok to agnd ...........................-0.3v to +6v out4, fb4 to agnd .................................-0.3v to (v pv4 + 0.3v) out5, fb5 to agnd .................................-0.3v to (v pv5 + 0.3v) lx1, lx2, lx3 continuous rms current (note 1).................1.5a bat continuous current .......................................................1.5a sys continuous current .......................................................1.5a continuous power dissipation (t a = +70?) 40-pin, 5mm x 5mm, thin qfn (derate 35.7mw/? above +70?)..............................................................2857mw operating junction temperature.....................................+150? storage junction temperature range ..............-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units dc power input (v dc = 5.0v, en = low) operating voltage 4.1 6.6 dc voltage range v dc withstand voltage 0 14 v sys regulation voltage v sys_reg v dc = 6v, usus = low, cen = high, system current is less than the input current limit 5.2 5.3 5.4 v dc undervoltage threshold v dcl v dc rising, 500mv typical hysteresis 3.95 4.00 4.05 v dc overvoltage threshold v dch v dc rising, 400mv typical hysteresis 6.8 6.9 7.0 v pen1 = low, pen2 = low, usus = low 90 95 100 pen1 = low, pen2 = high, usus = low 450 475 500 dc current limit i dclim v dc = 6v, v sys = 5v usb unconnected, cen = low, t a = +25?, vl = no load (note 3) pen1 = high, r diset = 3k 950 1000 1050 ma r diset resistance range 36k pen1 = low, usus = high 0.11 usus = low, cen = low; i sys = 0ma, i bat = 0ma, en = low; vl no load 1.1 dc quiescent current i dciq usus = low, cen = high; i sys = 0ma, v en = 0v, vl no load 0.7 ma minimum dc-to-bat voltage headroom v dc falling, 200mv hysteresis 0 15 30 mv minimum dc-to-sys voltage headroom v dc falling, 200mv hysteresis 0 15 30 mv dc-to-sys dropout resistance r ds v dc = 5v, i sys = 400ma, usus = low 0.325 0.600 note 1: lx_ has internal clamp diodes to pg_ and pv_. applications that forward bias these diodes must take care not to exceed the package power dissipation limits.
max8671x pmic with integrated charger and smart power selector for handheld devices _______________________________________________________________________________________ 5 parameter symbol conditions min typ max units starting dc when no usb present 1.0 ms dc-to-sys soft-start time t ss-d-s starting dc with usb present 35 ? dc thermal-limit temperature die temperature at which current limit is reduced +100 ? dc thermal-limit gain amount of input current reduction above thermal-limit temperature 5 %/? usb power input (v usb = 5.0v, en = low) operating voltage 4.1 6.6 usb voltage range v usb withstand voltage 0 14 v sys regulation voltage v sys_reg v usb = 6v, usus = low, cen = high, system current is less than the input current limit 5.2 5.3 5.4 v usb undervoltage threshold v usbl v usb rising, 500mv hysteresis 3.95 4.0 4.05 v usb overvoltage threshold v usbh v usb rising, 400mv hysteresis 6.8 6.9 7.0 v pen2 = low, usus = low 90 95 100 usb current limit i usblim v usb = 6v, v sys = 5v, dc unconnected, cen = low, t a = +25?, i vl = 0a (note 3) pen2 = high, usus = low 450 475 500 ma usus = high 0.11 usus = low, cen = low; i sys = 0ma, i bat = 0ma, vl no load 1.1 2.0 usb quiescent current i usbiq usus = low, cen = high; i sys = 0ma, vl no load 0.7 1.3 ma minimum usb-to-bat voltage headroom v usb falling, 200mv hysteresis 0 15 30 mv minimum usb-to-sys voltage headroom v usb falling, 200mv hysteresis 0 15 30 mv usb-to-sys dropout resistance r us v usb = 5v, i sys = 400ma, usus = low 0.325 0.600 usb-to-sys soft-start time t ss-u-s 1.0 ms usb thermal-limit temperature die temperature at which current limit is reduced 100 ? usb thermal-limit gain amount of input current reduction above thermal-limit temperature 5 %/? system (v dc = 5.0v, en = low) system operating voltage range v sys 2.6 5.5 v system undervoltage threshold v uvlo_sys sys falling, 100mv hysteresis 2.45 2.50 2.55 v electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices 6 _______________________________________________________________________________________ parameter symbol conditions min typ max units bat is sourcing 105ma 65 82 115 bat-to-sys reverse regulation voltage v bsreg dc or usb and bat are sourcing current bat is sourcing 905ma 130 mv dc and usb unconnected, en = low, v bat = 4v 010 v dc = v usb = 5v, usus = high, pen1 = low, en = low, v bat = 4v 010 dc and usb unconnected, en = high, v bat = 4v (step-down converters are not in dropout), pwm = low (note 4) 155 285 dc and usb unconnected, en = high, v bat = 2.8v (at least one step-down conver ter i s i n d r op out) , p w m = l ow ( n ote 4) 425 550 v dc = v usb = 5v, usus = high, en = high, v bat = 4v, pwm = low (note 4) 180 320 ? quiescent current i pv1 + i pv2 + i pv3 + i pv4 + i pv5 + i sys dc and usb unconnected, en = high, v bat = 4.0v, pwm = high 9ma battery charger (v dc = 5.0v, en = low) bat-to-sys on-resistance r bs v usb = 0v, v bat = 4.2v, i sys = 1a 0.08 0.16 t a = +25? 4.174 4.200 4.221 bvset = vl or bvset unconnected t a = -40? to +85? 4.145 4.200 4.242 t a = +25? 4.073 4.100 4.121 bvset = agnd t a = -40? to +85? 4.047 4.100 4.141 t a = +25? 4.325 4.350 4.376 bat regulation voltage (figure 6) v batreg r bvset = 49.9k to agnd t a = -40? to +85? 4.297 4.350 4.398 v bat recharge threshold v batrchg (note 5) -170 -120 -70 mv bat prequalification threshold v batprq v bat rising, 180mv hysteresis, figure 6 2.9 3.0 3.1 v r ciset resistance range guaranteed by bat fast-charge current limit 315k ciset voltage v ciset r ciset = 7.5k , i bat = 267ma, figure 9 0.9 1.0 1.1 v electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices _______________________________________________________________________________________ 7 parameter symbol conditions min typ max units low-power usb charging from the usb input, dc unconnected, r ciset = 3k , pen2 = low, usus = low 87 92 100 low-power usb charging from the dc input, r ciset = 3k , pen1 = low, pen2 = low, usus = low 87 92 100 high-power usb charging from the usb input, dc unconnected, r ciset = 3k , pen2 = high, usus = low 450 472 500 high-power usb charging from the dc input, r ciset = 3k , pen2 = high, usus = low 450 472 500 ac-to-dc adapter charging from the dc input, r diset = 3k , r ciset = 15k , pen1 = high 170 200 230 ac-to-dc adapter charging from the dc input, r diset = 3k , r ciset = 7.5k , pen1 = high 375 400 425 bat fast-charge current limit ac-to-dc adapter charging from the dc input, r diset = 3k , r ciset = 3.74k , pen1 = high 750 802 850 ma bat prequalification current v bat = 2.5v, r ciset = 3.74k 65 82 100 ma top-off threshold t a = +25?, r ciset = 3.74k (note 6) 20 30 40 ma no dc or usb power connected 0+5 bat leakage current en = low, t a = +25c dc and/or usb power connected, cen = high -5 1 +5 ? slew rate 450 ma/ms time from 0ma to 500ma 1.10 time from 0ma to 100ma 0.22 charger soft-start time t ss_chg time from 100ma to 500ma 0.88 ms timer accuracy c ct = 0.15? -20 +20 % timer suspend threshold ciset voltage when the fast-charge timer suspends; 300mv translates to 20% of the maximum fast-charge current limit 250 300 350 mv timer extend threshold ciset voltage when the fast-charge timer suspends; 750mv translates to 50% of the maximum fast-charge current limit 700 750 800 mv electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices 8 _______________________________________________________________________________________ parameter symbol conditions min typ max units prequalification time t pq c ct = 0.15? 33 min fast-charge time t fc c ct = 0.15? 660 min top-off time t to 15 s thermistor input (thm) (v dc = 5.0v, en = low) thm threshold, cold v thmc v thm rising, 65mv hysteresis 73.0 74.0 75.5 % of v vl thm threshold, hot v thmh v thm falling, 65mv hysteresis 27.0 28.4 30.0 % of v vl thm = agnd or vl, t a = +25? -0.100 0.001 +0.200 thm input leakage current i thm thm = agnd or vl, t a = +85? 0.01 ? power sequencing (figures 11 and 12) en to reg3 enable delay t d1 120 ? reg1 soft-start time t ss1 2.6 ms reg3 to reg1/2 delay t d2 0.4 ms reg2 soft-start time t ss2 2.6 ms reg3 soft-start time t ss3 2.6 ms reg1/2 to reg4 delay t d3 0.3 ms reg4 soft-start time t ss4 3.0 ms reg5 soft-start time t ss5 3.0 ms regulator thermal shutdown thermal shutdown temperature t j rising +165 ? thermal shutdown hysteresis 15 ? reg1?ynchronous step-down converter input voltage pv1 supplied from sys v sys v maximum output current l = 4.7?, r l = 0.13 (note 7) 425 ma fb1 voltage (note 8) 0.997 1.012 1.028 v adjustable output voltage range 1 v sys v t a = +25? -50 -5 +50 fb1 leakage current v fb1 = 1.012v t a = +85? -5 na load regulation pwm mode 4.4 %/a line regulation pwm mode (note 9) 1 %/d p-channel on-resistance v pv1 = 4v, i lx1 = 180ma 165 330 m n-channel on-resistance v pv1 = 4v, i lx1 = 180ma 200 400 m p-channel current-limit threshold 0.555 0.615 0.675 a electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices _______________________________________________________________________________________ 9 parameter symbol conditions min typ max units skip mode transition current (note 10) 60 ma n-channel zero-crossing threshold 10 ma maximum duty cycle 100 % minimum duty cycle pwm mode 12.5 % internal oscillator frequency 1.8 2.0 2.2 mhz internal discharge resistance in shutdown en = low, resistance from lx1 to pg1 0.5 1.0 2.0 k reg2?ynchronous step-down converter input voltage pv2 supplied from sys v sys v maximum output current l = 4.7?, r l = 0.13 (note 7) 425 ma fb2 voltage (note 8) 0.997 1.012 1.028 v adjustable output voltage range 1 v sys v t a = +25? -50 -5 +50 fb2 leakage current v fb2 = 1.012v t a = +85? -50 na load regulation pwm mode 4.4 %/a line regulation pwm mode (note 9) 1 %/d p-channel on-resistance v pv2 = 4v, i lx2 = 180ma 200 400 m n-channel on-resistance v pv2 = 4v, i lx2 = 180ma 150 265 m p-channel current-limit threshold 0.555 0.615 0.675 a skip mode transition current (note 10) 60 ma n-channel zero-crossing threshold 10 ma maximum duty cycle 100 % minimum duty cycle pwm mode 12.5 % internal oscillator frequency 1.8 2.0 2.2 mhz internal discharge resistance in shutdown en = low, resistance from lx2 to pg2 0.5 1.0 2.0 k reg3?ynchronous step-down converter input voltage pv3 supplied from sys v sys v maximum output current l = 4.7?, r l = 0.13 (note 7) 425 ma fb3 voltage (note 8) 0.997 1.012 1.028 v adjustable output voltage range 1 v sys v t a = +25? -50 -5 +50 fb3 leakage current v fb2 = 1.012v t a = +85? -50 na load regulation pwm mode 4.4 %/a electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices 10 ______________________________________________________________________________________ parameter symbol conditions min typ max units line regulation pwm mode (note 9) 1 %/d p-channel current-limit threshold 0.555 0.615 0.675 a skip mode transition current (note 10) 60 ma n-channel zero-crossing threshold 10 ma p-channel on-resistance v pv3 = 4v, i lx3 = 180ma 230 460 m n-channel on-resistance v pv3 = 4v, i lx3 = 180ma 120 210 m maximum duty cycle 100 % minimum duty cycle pwm mode 12.5 % internal oscillator frequency 1.8 2.0 2.2 mhz internal discharge resistance in shutdown en = low, resistance from lx3 to pg3 0.5 1.0 2.0 k reg4?inear regulator pv4 operating range v pv4 1.7 v sys v pv4 undervoltage lockout threshold v pv4 rising, 100mv hysteresis 1.55 1.60 1.65 v fb4 voltage no load 0.582 0.600 0.618 v t a = +25? -50 -5 +50 fb4 leakage current v fb4 = 0.6v t a = +85? -5 na pv4 to out4, v pv4 = 3.3v 0.45 drop-out resistance pv4 to out4, v pv4 = 2.0v 0.75 1.8 v fb4 = 0.54v 200 230 265 current limit v fb4 = 0v 235 ma output noise 10hz to 100khz; c out4 = 3.3?, i out4 = 10ma, v pv4 = 2v, v out4 set for 1.8v 120 ? rms f = 1khz, i out4 = 10ma, v pv4 = 2v, v out4 set for 1.8v 67 psrr f = 10khz, i out4 = 10ma, v pv4 = 2v, v out4 set for 1.8v 50 db internal discharge resistance in shutdown en = low, resistance from out4 to agnd 0.5 1.0 2.0 k electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 11 parameter symbol conditions min typ max units reg5?inear regulator pv5 operating range v pv5 1.7 v sys v pv5 undervoltage lockout threshold v pv5 rising, 100mv hysteresis 1.55 1.60 1.65 v fb5 voltage no load 0.582 0.600 0.618 v t a = +25? -50 -5 +50 fb5 leakage current v fb5 = 0.6v t a = +85? -5 na v pv5 to out5, v pv5 = 3.3v 0.45 drop-out resistance v pv5 to out5, v pv5 = 2.0v 0.75 1.8 v fb5 = 0.54v 200 230 265 current limit v fb5 = 0v 235 ma output noise 10hz to 100khz, c ou t5 = 2.2f, i ou t5 = 10m a, v p v 5 = 3.5v , v ou t5 set for 3.3v 180 ? rms f = 1khz, i out5 = 10ma, v pv5 = 3.5v, v out5 set for 3.3v 62 psrr f = 10khz, i out5 = 10ma, v pv5 = 3.5v, v out5 set for 3.3v 44 db internal discharge resistance in shutdown en = low, resistance from out5 to agnd 0.5 1.0 2.0 k vl?inear regulator vl voltage v vl i vl = 0ma to 3ma 3.0 3.3 3.6 v logic ( uok , dok , pen1, pen2, usus, cen , cst1, cst2, en, pwm) logic input-voltage low v usb or v dc = 4.1v to 6.6v, v sys = 2.6v to 5.5v 0.6 v logic input-voltage high v usb or v dc = 4.1v to 6.6v, v sys = 2.6v to 5.5v 1.3 v t a = +25? 0.001 1 logic input leakage current v logic = 0v to 5.5v t a = +85? 0.01 ? logic output-voltage low i sink = 1ma 10 30 mv t a = +25? 0.001 1 logic output-high leakage current v logic = 5.5v t a = +85? 0.01 ? tri-state input (bvset) bvset input-voltage low v usb or v dc = 4.1v to 6.6v 0.3 v bvset input-voltage mid v usb or v dc = 4.1v to 6.6v 1.2 v vl - 1.2 v electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices 12 ______________________________________________________________________________________ note 2: limits are 100% production tested at t a = +25?. limits over the operating temperature range are guaranteed through cor- relation using statistical quality control (sqc) methods. note 3: the usb/dc current limit does not include the vl output current. see the vl linear regulator section for more information. note 4: quiescent current excludes the energy needed for the reg1?eg5 external resistor-dividers. all typical operating charac- teristics include the energy for the reg1?eg5 external resistor-dividers. for the circuit of figure 1, the typical quiescent current with dc and usb unconnected, en = high, v bat = 4v, and pwm = low is 175?. note 5: the charger transitions from done to fast-charge mode at this bat recharge threshold (figure 7). note 6: the charger transitions from fast-charge to top-off mode at this top-off threshold (figure 7). note 7: the maximum output current is guaranteed by correlation to the p-channel current-limit threshold, p-channel on-resistance, n-channel on-resistance, oscillator frequency, input voltage range, and output voltage range. the parameter is stated for a 4.7? inductor with 0.13 series resistance. see the step-down converter output current section for more information. note 8: the step-down output voltages are 1% high with no load due to the load-line architecture. when calculating the external resistor-dividers, use an fb_ voltage of 1.000v. note 9: line regulation for the step-down converters is measured as v out / d, where d is the duty cycle (approximately v out /v in ). note 10: the skip mode current threshold is the transition point between fixed-frequency pwm operation and skip mode operation. the specification is given in terms of output load current for inductor values shown in the typical application circuits. parameter symbol conditions min typ max units bvset input-voltage high v usb or v dc = 4.1v to 6.6v v vl - 0.3 v vl + 0.3 v internal bvset pullup resistance 52.5 k external bvset pulldown resistance for midrange voltage r bvset 45 50 55 k electrical characteristics (continued) (dc, usb, bvset, uok , dok , lx_ unconnected; v thm = v l /2, v pg_ = v agnd = 0v, v bat = 4v, cen = low, usus = low, en = high, v pen1 = v pen2 = 3.3v, v pwm = 0v, c out4 = 1?, c out5 = 1?, c sys = 10?, pv1 = pv2 = pv3 = pv4 = pv5 = sys, r diset = 3k , r ciset = 3k , c vl = 0.1?, c ct = 0.15?, c bp = 0.01?, v fb1 = 1.1v, v fb2 = 1.1v, v fb3 = 1.1v, t a = -40? to +85?, unless other- wise noted.) (note 2)
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 13 0 0.4 0.2 0.8 0.6 1.0 1.2 1.4 1.6 046 2 8 10 12 14 16 quiescent current vs. dc or usb supply voltage max8671x toc01 input voltage (v) input current (ma) charger enabled no battery input voltage at dc or usb with the other input left unconnected falling rising 0 0.4 0.2 0.8 0.6 1.0 1.2 1.4 1.6 046 2 8 10 12 14 16 quiescent current vs. dc or usb supply voltage max8671x toc02 input voltage (v) input current (ma) charger enabled no battery input voltage at dc or usb with the other input left unconnected falling rising 0 0.10 0.05 0.20 0.15 0.30 0.25 0.35 0.45 0.40 0.50 046 2 8 10 12 14 16 usb quiescent current vs. usb supply voltage, usb suspend max8671x toc03 usb voltage (v) usb current (ma) usb voltage rising 0 0.4 0.2 0.8 0.6 1.2 1.0 1.4 0 1.0 1.5 0.5 2.0 2.5 3.0 3.5 4.0 4.5 battery leakage current vs. battery voltage when regulators are powered from usb max8671x toc04 battery voltage (v) battery leakage current ( a) v usb = 5v v dc = 0v pen1 = pen2 = 1 en = 1 0 0.2 0.1 0.5 0.4 0.3 0.7 0.6 0.8 0 1.5 2.0 0.5 1.0 2.5 3.0 3.5 4.0 4.5 battery leakage current vs. battery voltage max8671x toc05 battery voltage (v) battery leakage current ( a) no external power en = low cen = high typical operating characteristics (circuit of figure 1, i vl = 0ma, t a = +25?, unless otherwise noted.)
max8671x pmic with integrated charger and smart power selector for handheld devices 14 ______________________________________________________________________________________ 3.00 3.50 4.50 4.00 5.00 5.50 0 400 200 600 800 1000 v sys vs. sys current max8671x toc12 sys current (ma) v sys (v) dc open, v usb = 5.1v, v bat = 4.0v pen1 = 1, pen2 = 0, charger disabled 3.00 3.50 4.50 4.00 5.00 5.50 0 400 200 600 800 1000 v sys vs. sys current max8671x toc13 sys current (ma) v sys (v) dc open, v usb = 5.1v, v bat = 4.0v pen1 = 1, pen2 = 0, charger disabled 0 150 100 50 200 250 300 350 400 450 500 2.0 3.0 2.5 3.5 4.0 4.5 charge current vs. battery voltage with usb input max8671x toc06 battery voltage (v) charge current (ma) pen2 = 1 v usb = 5.0v v dc = 0v pen1 = 1 pen2 = 0 0 150 100 50 200 250 300 350 400 450 500 2.0 3.0 2.5 3.5 4.0 4.5 charge current vs. battery voltage max8671x toc07 battery voltage (v) charge current (ma) r ciset = 10k v usb = 5.0v v dc = 0v pen1 = 1, pen2 = 1 r ciset = 6.04k 0 150 100 50 200 250 300 350 400 450 500 -40 10 -15 35 60 85 charge current vs. ambient temperature, low power dissipation max8671x toc08 ambient temperature ( c) charge current (ma) v usb = 5.0v v dc = 0v v bat = 4.0v pen1 = 1 pen2 = 1 pen2 = 0 0 150 100 50 200 250 300 350 400 450 500 -40 10 -15 35 60 85 charge current vs. ambient temperature, high ic power dissipation max8671x toc09 ambient temperature ( c) charge current (ma) v usb = 6.5v v dc = 0v v bat = 3.1v pen1 = 1 pen2 = 1 pen2 = 0 4.00 4.15 4.10 4.05 4.20 4.25 4.30 4.35 4.40 4.45 4.50 -40 10 -15 35 60 85 battery regulation voltage vs. temperature max8671x toc10 ambient temperature ( c) battery voltage (v) v usb = 5v v dc = 0v pen1 = 1 pen2 = 0 bvset = vl no load 3.80 3.90 3.85 4.00 3.95 4.05 4.10 0 400 200 600 800 1000 v sys vs. sys current max8671x toc11 sys current (ma) v sys (v) dc open, usb open, v bat = 4.0v the slope shows the system load switch has an on-resistance of 81m . typical operating characteristics (continued) (circuit of figure 1, i vl = 0ma, t a = +25?, unless otherwise noted.)
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 15 2ms/div usb connect (no sys load) v usb i usb 2v/div 500ma/div 5v/div 5v/div max8671x toc14 v uok v sys i bat 4.0v 500ma/div 4.14v -475ma charging 0ma 0ma load on sys, 4.0v battery, 5.0v usb input typical operating characteristics (continued) (circuit of figure 1, i vl = 0ma, t a = +25?, unless otherwise noted.) 2ms/div usb connect (50ma sys load) v usb i usb 2v/div 500ma/div 5v/div 5v/div max8671x toc15 v uok v sys i bat 4.0v 500ma/div 4.14v -425ma charging +50ma 50ma load on sys, 4.0v battery, 5.0v usb input 2ms/div usb disconnect (50ma sys load) v usb i usb 2v/div 500ma/div 5v/div 5v/div max8671x toc16 v uok v sys i bat 4.0v 500ma/div 4.14v -425ma charging 50ma load on sys, 4.0v battery, 5.0v usb input +50ma 400 s/div usb suspend v usb i usb 5v/div 2v/div 500ma/div 5v/div 5v/div max8671x toc17 v cst1 v cst2 v sys i bat 4.0v 500ma/div 4.14v 50ma load on sys, 4.0v battery, 5.0v usb input +50ma -425ma 400 s/div usb resume v usus i usb 5v/div 2v/div 500ma/div 5v/div 5v/div max8671x toc18 v cst1 v cst2 v sys i bat 4.0v 500ma/div 4.14v 50ma load on sys, 4.0v battery, 5.0v usb input +50ma -425ma
max8671x pmic with integrated charger and smart power selector for handheld devices 16 ______________________________________________________________________________________ 4ms/div power-up sequencing v en v out1 v out2 v out3 v out4 v out5 v vl i usb 50ma/div 5v/div 5v/div 5v/div 2v/div 5v/div 5v/div 5v/div max8671x toc22 400 s/div ac-to-dc adapter connect with usb v sys i dc 500ma/div 500ma/div 5v/div max8671x toc19 i usb i bat 4.0v 500ma/div 4.14v 25 load on sys, pen1 = pen2 = high 1a dc limit, r diset = 3.01k -330ma -840ma 1a 400 s/div ac-to-dc adapter connect with no usb v sys i dc 500ma/div 2v/div max8671x toc20 i bat 4v 500ma/div 4.14v 25 load on sys, pen1 = pen2 = high 1a dc limit +160ma 1a -840ma 20ms/div ac-to-dc adapter disconnect with usb v sys i dc 500ma/div 500ma/div 2v/div max8671x toc21 i bat i usb 4v 500ma/div 4.14v 25 load on sys, pen1 = pen2 = high 1a dc limit -840ma 1a +160ma -330ma typical operating characteristics (continued) (circuit of figure 1, i vl = 0ma, t a = +25?, unless otherwise noted.)
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 17 typical operating characteristics (continued) (circuit of figure 1, i vl = 0ma, t a = +25?, unless otherwise noted.) reg1 efficiency vs. load current max8671x toc23 load current (ma) efficiency (%) 100 10 10 20 30 40 50 60 70 80 90 100 0 1 1000 pwm = 0 v out1 = 2.8v pwm = 1 v out1 = 2.8v v batt = 4v 2.700 2.760 2.740 2.720 2.780 2.800 2.820 2.840 2.860 2.880 2.900 0 100 50 150 200 250 reg1 load regulation max8671x toc24 output current (ma) output voltage (v) r fbh = 182k r fbl = 100k 4 s/div reg1 light-load switching waveforms (pwm = 0) v out1 v lx1 i li max8671x toc26 200ma/div 0 0 2v/div 20mv/div (ac-coupled) 20ma load 200ns/div reg1 light-load switching waveforms (pwm = 1) v out1 v lx1 i li max8671x toc27 100ma/div 0 0 2v/div 10mv/div 20ma load 400ns/div reg1 heavy-load switching waveforms v out1 v lx1 i li max8671x toc28 100ma/div 0 0 2v/div 10mv/div (ac-coupled) 20ma load 100 s/div reg1 line transient v sys v out1 max8671x toc29 20mv/div 2v/div 25ma load 3.3v 5.3v 3.3v 20 s/div reg1 load transient i out1 v out1 max8671x toc30 100ma/div 50mv/div (ac-coupled) 250ma 25ma 25ma 0 60 40 20 80 100 120 140 160 180 200 0 200 100 300 400 500 reg1 dropout voltage vs. load current max8671x toc25 output current (ma) dropout voltage (mv) v out1 = 3.3v v out1 = 2.8v the nominal inductor dc resistance is 140m . the nominal p-channel resistance of the regulator is 200m at 2.8v and 185m at 3.3v. the slope of the line shows that the total dropout resistance of an average part, board, inductor combination is 330m at 3.3v and 354m at 2.8v. sys is 100mv below the reg1 nominal regulation voltage.
max8671x pmic with integrated charger and smart power selector for handheld devices 18 ______________________________________________________________________________________ reg2 load regulation max8671x toc32 output current (ma) output voltage (v) 200 150 100 50 1.45 1.50 1.55 1.60 1.40 0 250 1.10 1.16 1.14 1.12 1.18 1.20 1.22 1.24 1.26 1.28 1.30 0 100 50 150 200 250 reg3 load regulation max8671x toc34 output current (ma) output voltage (v) r fbh = 20k r fbl = 100k 10 s/div out3 light-load switching waveforms (pwm = 0) i l1 v out1 v lx1 max8671x toc35 200ma/div 20mv/div 2v/div 10ma load 0 400ns/div out3 heavy-load switching waveforms i l1 v out1 v lx1 max8671x toc36 200ma/div 10mv/div 2v/div 250ma load 0 40 s/div out3 load transient i out1 v out1 max8671x toc37 100ma/div 100mv/div 250ma 25ma 25ma pwm = 0 0 30 20 10 40 50 60 70 80 90 100 1 10 100 1000 reg3 efficiency vs. load current max8671x toc33 load current (ma) efficiency (%) pwm = 0 v out2 = 1.2v pwm = 1 v out2 = 1.2v v batt = 4.0v typical operating characteristics (continued) (circuit of figure 1, i vl = 0ma, t a = +25?, unless otherwise noted.) 0 30 20 10 40 50 60 70 80 90 100 1 10 100 1000 reg2 efficiency vs. load current max8671x toc31 load current (ma) efficiency (%) pwm = 0 v out2 = 1.5v pwm = 1 v out2 = 1.5v v batt = 4.0v
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 19 typical operating characteristics (continued) (circuit of figure 1, i vl = 0ma, t a = +25?, unless otherwise noted.) 2.534 2.540 2.538 2.536 2.542 2.544 2.546 2.548 2.550 2.552 2.554 050 100 150 reg4 load regulation max8671x toc38 output current (ma) output voltage (v) r fbh = 316k r fbl = 100k v sys = 4v 3.240 3.246 3.244 3.242 3.248 3.250 3.252 3.254 3.256 3.258 3.260 050 100 150 reg5 load regulation max8671x toc41 output current (ma) output voltage (v) v usb = 5v 100 s/div reg4 line transient v out4 v pv4 max8671x toc39 10mv/div 2v/div 3.3v 5.3v 3.3v pv = sys 13.4 load 40 s/div reg4 load transient i out4 v out4 max8671x toc40 100mv/div 50mv/div 150ma 50ma 50ma v pv4 = v sys = 4v v out4 = 2.5v 40 s/div reg5 load transient i out5 v out5 max8671x toc42 100mv/div 50mv/div 150ma 50ma 50ma v usb = 5v, v out5 = 3.3v
max8671x pmic with integrated charger and smart power selector for handheld devices 20 ______________________________________________________________________________________ pin description pin name function 1 usus usb suspend digital input. as shown in table 1, driving usus high suspends the dc or usb inputs if they are configured as a usb power input. 2dc dc power input. dc is capable of delivering 1a to sys. dc supports both ac adaptors and usb inputs. as shown in table 1, the dc current limit is controlled by pen1, pen2, usus, and r diset . 3 usb usb power input. usb is capable of delivering 0.5a to sys. as shown in table 1, the usb current limit is controlled by pen1, pen2, and usus. 4 fb5 feedback input for reg5. connect fb5 to the center of a resistor voltage-divider from out5 to agnd to set the reg5 output voltage from 0.6v to v pv5 . 5 pv5 power input for reg5. connect pv5 to sys, or a supply between 1.7v and v sys . bypass pv5 to power ground with a 1? ceramic capacitor. 6 out5 linear regulator power output. out5 is internally pulled to agnd by 1k in shutdown. 7 pg2 power ground for the reg2 step-down regulator 8 lx2 inductor switching node for reg2. lx2 is internally pulled to pg2 by 1k in shutdown. 9 pv2 power input for the reg2 step-down regulator. connect pv2 to sys. bypass pv2 to pg2 with a 4.7? ceramic capacitor. 10 cen active-low charger enable input. pull cen low to enable the charger, or drive cen high to disable charging. the battery charger is also disabled when usus is high. 11 fb2 feedback input for reg2. connect fb2 to the center of a resistor voltage-divider from the reg2 output capacitors to agnd to set the output voltage from 1v to v sys . 12 dok active-low, open-drain dc power-ok output. dok is low when v dc is within its valid operating range. 13 fb4 feedback input for reg4. connect fb4 to the center of a resistor voltage-divider from the reg4 output capacitors to agnd to set the output voltage from 0.6v to v pv4 . 14 bp reference noise bypass. bypass bp with a low-leakage 0.01? ceramic capacitor for reduced noise on the ldo outputs. 15 out4 linear regulator power output. out4 is internally pulled to agnd in shutdown. 16 pv4 power input for reg4. connect pv4 to sys, or a supply between 1.7v and v sys . bypass pv4 to power ground with a 1? ceramic capacitor. 17 bvset battery regulation voltage set node. drive bvset low to set the regulation voltage to 4.1v. connect bvset to vl or leave unconnected to set the regulation voltage to 4.2v. connect bvset to agnd through a 50k resistor to set the regulation voltage to 4.350v. 18 agnd ground. agnd is the low-noise ground connection for the internal circuitry. 19 fb1 feedback input for reg1. connect fb1 to the center of a resistor voltage-divider from the reg1 output capacitors to agnd to set the output voltage from 1v to v sys . 20 en regulator enable input. drive en high to enable all regulator outputs. the sequencing is shown in figure 11. drive en low to disable the regulators. 21 pwm forced-pwm input. connect pwm high for forced-pwm operation on reg1, reg2, and reg3. connect pwm low for auto pwm operation. do not change pwm on-the-fly. see the pwm section for more information. 22 pv1 power input for the reg1 step-down regulator. connect pv1 to sys. bypass pv1 to pg1 with a 4.7? ceramic capacitor.
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 21 pin description (continued) pin name function 23 lx1 inductor switching node for reg1. lx1 is internally pulled to pg1 by 1k in shutdown. 24 pg1 power ground for the reg1 step-down regulator 25 pg3 power ground for the reg3 step-down regulator 26 lx3 inductor switching node for reg3. lx3 is internally pulled to pg3 by 1k in shutdown. 27 pv3 power input for the reg3 step-down regulator. connect pv3 to sys. bypass pv3 to pg3 with a 4.7? ceramic capacitor. 28 vl ic supply output. vl is an ldo output that powers the max8671x internal battery-charger circuitry. vl provides 3.3v at 3ma to power external circuitry when dc or usb is present. connect a 0.1? capacitor from vl to agnd. 29 fb3 feedback input for reg3. connect fb3 to the center of a resistor voltage-divider from the reg3 output capacitors to agnd to set the output voltage from 1v to v sys . 30 diset dc input current-limit select input. connect a resistor from diset to agnd (r diset ) to set the dc current limit. see table 2 for more information. 31 ciset charge rate select input. connect a resistor from ciset to agnd (r ciset ) to set the fast-charge current limit, prequalification-charge current limit, and top-off threshold. 32 ct charge timer programming node. connect a capacitor from ct to agnd (c ct ) to set the time required for a fault to occur in fast-charge or prequalification modes. connect ct to agnd to disable the fast-charge and prequalification timers. 33 thm thermistor input. connect a negative temperature coefficient (ntc) thermistor that has a good thermal contact with the battery from thm to agnd. connect a resistor equal to the thermistor resistance at +25? from thm to vl. charging is suspended when the battery is outside the hot or cold limits. 34 bat positive battery terminal connection. connect bat to the positive terminal of a single-cell li+/li-poly battery. 35 sys system supply output. bypass sys to power ground with a 10? ceramic capacitor. when a valid voltage is present at usb or dc and not suspended (usus = low), sys is limited to 5.3v (v sys-reg ). when the system load (i sys ) exceeds the input current limit, sys drops below v bat by v bsreg allowing both the external power source and the battery service sys. sys is connected to bat through an internal system load switch (r bs ) when a valid source is not present at usb or dc. 36 pen1 input current-limit control 1. see table 1 for more information. 37 cst2 open-drain charger status output 2. cst1 and cst2 indicate four different charger states. see table 3 for more information. 38 uok active-low, open-drain usb power-ok output. uok is low when v usb is within its valid operating range. 39 cst1 open-drain charger status output 1. cst1 and cst2 indicate four different charger states. see table 3 for more information. 40 pen2 input current-limit control 2. see table 1 for more information. ?p exposed paddle. connect the exposed paddle to agnd. connecting the exposed paddle does not remove the requirement for proper ground connections to agnd, pg1, pg2, and pg3.
max8671x pmic with integrated charger and smart power selector for handheld devices 22 ______________________________________________________________________________________ ep dc usb bat + li+/li-poly sys vl 3.3v 3ma bat pv4 out4 out4 1.8v 180ma out2 sys ac-to-dc adapter vbus dok uok usus pen1 cen en diset ciset ct cst1 cst2 pwm fb2 pv2 pg2 lx2 out2 sys lx3 fb3 pv3 pg3 out3 sys lx1 fb1 pv1 2.8v 425ma 2.0v 425ma 1.2v 425ma pg1 out1 sys 10 f 4.7 f 0.1 f 4.7 f 4.7 f 4.7 f 4.7 f 4.7 h 0.6a 4.7 h 0.6a 4.7 h 0.6a 2x 10 f 2x 10 f 2x 10 f 0.15 f 3k 3k 4.7 f 1.0 f 2.2 f io 4x 560k 5% p pen2 bp 0.01 f pv5 out5 out5 3.3v 180ma sys 1.0 f 2.2 f 10k vl 39 37 12 38 182k 100k 100k 100k 20k 100k bvset 17 14 30 31 32 25 27 29 26 7 9 11 35 34 33 23 19 22 24 8 36 40 1 10 21 20 off on 60.4k 274k 4 5 6 2 3 28 18 15 16 13 max8671x thm agnd fb5 fb4 10k = 3380k t vl 121k 60.4k figure 1. max8671x typical application circuit
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 23 dc usb smart power selector diset pen1 pen2 usus li+/li-poly battery charger and system load switch sys bat uok dok cst2 thm cst1 cen ct highest voltage selector vl agnd 3.3v ldo in out reg1 dc-dc pv1 lx1 pg1 fb1 reg2 dc-dc pv2 lx2 pg2 fb2 reg3 dc-dc pv3 lx3 pg3 fb3 reg4 ldo pv4 out4 reg5 ldo pv5 out5 bp ref fb5 en pwm ciset smart power selector and charger bias bvset fb4 max8671x figure 2. functional diagram
max8671x pmic with integrated charger and smart power selector for handheld devices 24 ______________________________________________________________________________________ power source dok uok pen1 pen2 usus dc input current limit usb input current limit maximum charge current* ac-to-dc adapter at dc input lxhx x i dclim lower of i chgmax and i dclim l x l l l 100ma lower of i chgmax and 100ma l x l h l 500ma lower of i chgmax and 500ma usb power at dc input l x l x h suspend usb input off, dc input has priority 0 h l x l l 100ma lower of i chgmax and 100ma h l x h l 500ma lower of i chgmax and 500ma usb power at usb input, dc unconnected h l x x h suspend 0 dc and usb unconnected hhx x x no dc input no usb input 0 table 1. input limiter control logic * charge current cannot exceed the input current limit. charge can be less than the maximum charge current if the total sys load exceeds the input current limit. x = don? care. detailed description the max8671x highly integrated pmic is ideally suited for use in portable audio player and handheld applica- tions. as shown in figure 2, the max8671x integrates usb power input, ac-to-dc adapter power input (dc), li+/li-poly battery charger, three step-down regulators, two linear regulators, and various monitoring and status outputs. the max8671x offers adjustable output volt- ages for all outputs. smart power selector the max8671x smart power selector seamlessly dis- tributes power between the two current-limited external inputs (usb and dc), the battery (bat), and the sys- tem load (sys). the basic functions performed are: with both an external power supply (usb or dc) and battery (bat) connected: when the system load requirements are less than the input current limit, the battery is charged with residual power from the input. when the system load requirements exceed the input current limit, the battery supplies supple- mental current to the load through the internal sys- tem load switch. when the battery is connected and there is no exter- nal power input, the system (sys) is powered from the battery. when an external power input is connected and there is no battery, the system (sys) is powered from the external power input. the dual-input smart power selector supports end products with dual and single external power inputs. for end products with dual external power inputs, con- nect these inputs directly to the dc and usb nodes of the max8671x. for end products with a single input, connect the single input to the dc node and connect usb to ground or leave it unconnected. in addition to ac-to-dc adapters current limits, the dc input also supports usb current limit to allow for end products
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 25 with a single power input to operate from either an ac- to-dc adapter or usb host (see table 1). a thermal-limiting circuit reduces the battery charger rate and external power-source current to prevent the max8671x from overheating. system load switch an internal 80m (r bs ) mosfet connects sys to bat when no voltage source is available at dc or usb. when an external source is detected at dc or usb, this switch is opened and sys is powered from the valid input source through the smart power selector. when the system load requirements exceed the input current limit, the battery supplies supplemental current to the load through the internal system load switch. if the system load continuously exceeds the input current limit, the battery does not charge, even though external power is connected. this is not expected to occur in most cases because high loads usually occur only in short peaks. during these peaks, battery energy is used, but at all other times the battery charges. usb power input (usb) usb is a current-limited power input that supplies the system (sys) up to 500ma. the usb to sys switch is a linear regulator designed to operate in dropout. this lin- ear regulator prevents the sys voltage from exceeding 5.3v. usb is typically connected to the v bus line of the universal serial bus (usb) interface. as shown in table 1, usb supports three different current limits that are set with the pen2 and usus digital inputs. these cur- rent limits are ideally suited for use with usb power. the operating voltage range for usb is 4.1v to 6.6v, but it can tolerate up to 14v without damage. when the usb input voltage is below the undervoltage threshold (v usbl , 4v typ) it is considered invalid. similarly, if the usb voltage is above the overvoltage threshold (v usbh , 6.9v typ) it is considered invalid. when the usb voltage is below the battery voltage, it is consid- ered invalid. the usb power input is disconnected when the usb voltage is invalid. as shown in table 1, when power is available at the dc input, it has priority over the usb input. bypass usb to ground with at least a 4.7? capacitor. to support usb power sources at the usb input drive pen2 and usus to select between three internally set usb-related current limits as shown in table 1. choose 100ma for low-power usb mode. choose 500ma for high-power usb mode. choose suspend to reduce the usb current to 0.11ma (typ) for both usb suspend mode and unconfigured otg mode. to comply with the usb 2.0 specification, each device must be initially configured for low power. after usb enumeration, the device can switch from low power to high power if given permission from the usb host. the max8671x does not perform enumeration. it is expected that the system communicates with the usb host and com- mands the max8671x through its pen1, pen2, and usus inputs. when the load exceeds the input current limit, sys drops to 82mv below bat and the battery supplies supplemental load current. the max8671x reduces the usb current limit by 5%/? when the die temperature exceeds +100?. the sys- tem load (i sys ) has priority over the charger current, so input current is first reduced by lowering charge cur- rent. if the junction temperature still reaches +120? in spite of charge current reduction, no input current is drawn from usb; the battery supplies the entire load and sys is regulated below bat by v bsreg . note that this on-chip thermal-limiting circuit is not related to and operates independently from the thermistor input. if the usb power input is not required, connect usb to ground or leave it unconnected. when both dc and usb inputs are powered, the dc input has priority.
max8671x pmic with integrated charger and smart power selector for handheld devices 26 ______________________________________________________________________________________ usb power-ok output ( uok ) as shown figure 3, the usb power-ok output ( uok ) is an active-low open-drain output. the uok output pulls low when the voltage from usb to agnd (v usb ) is between v usbh (typically 6.9v) and v usbl (typically 4.0v). the usb power-ok circuitry remains active in thermal overload and usb suspend. if the usb power-ok out- put feature is not required, connect uok to ground or leave unconnected. usb suspend (usus) as shown in table 1, driving usus high suspends the dc or usb inputs if they are configured as a usb power input. the suspend current is 110? when usus is driven high allowing the max8671x to comply with the usb 1.1/2.0 specification for usb suspend as well as the usb otg specification for an unconfigured device. if an external input (usb or dc) is connected to the max8671x and suspended, the sys node is sup- ported by the battery. the dok, uok, and vl circuits remain active in usb suspend mode. a common assumption is that reg5 is disabled in usb suspend. this is not true. reg5 is not affected by the usb suspend mode. while in suspend, a usb device must provide the 3.3v termination to the usb trans- ceivers?pullup resistors. this 3.3v termination can come from the max8671x? vl output or reg5. both remain enabled in usb suspend. dc power input (dc) dc is a current-limited power input that supplies the system (sys) up to 1a. the dc-to-sys switch is a lin- ear regulator designed to operate in dropout. this lin- ear regulator prevents the sys voltage from exceeding 5.3v. as shown in table 1, dc supports four different current limits that are set with the pen1, pen2, and usus digital inputs. these current limits are ideally suited for use with ac-to-dc wall adapters and usb power. the operating voltage range for dc is 4.1v to 6.6v, but it can tolerate up to 14v without damage. when the dc input voltage is below the undervoltage threshold (v dcl , 4v typ), it is considered invalid. similarly, if the dc voltage is above the overvoltage threshold (v dch , 6.9v typ), it is considered invalid. when the dc voltage is below the battery voltage, it is considered invalid. the dc power input is disconnect- ed when the dc voltage is invalid. as shown in table 1, when power is available at the dc input, it has priority over the usb input. bypass dc to ground with at least a 4.7? capacitor. uok v usbl 4.0v rising (typ) 500mv hyst v usbh 6.9v rising (typ) 400mv hyst usb usb undervoltage usb overvoltage agnd max8671x figure 3. usb power-ok logic
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 27 to support common 500ma to 1000ma wall adapters at the dc input, pull pen1 high. with pen1 pulled high, the dc current limit is set by an external resistor from diset to agnd (r diset ). choose r diset based on the current capability of the ac-to-dc adapter (i adptr ) as follows: for the selected value of r diset , calculate the dc cur- rent limit (i dclim ) as follows (table 2, figure 4): to support usb power sources at the dc input, pull pen1 low. with pen1 low, drive pen2 and usus to select between three internally set usb-related current limits as shown in table 1. choose 100ma for low- power usb mode. choose 500ma for high-power usb mode. choose suspend to reduce the dc current to 0.11ma (typ) for both usb suspend mode and uncon- figured otg mode. to comply with the usb 2.0 specifi- cation, each device must be initially configured for low power. after usb enumeration, the device can switch from low power to high power if given permission from the usb host. when the load exceeds the current limit, sys drops below bat by v bsreg and the battery sup- plies supplemental load current. if the dc power input is not required, connect dc to ground or leave it unconnected. the max8671x reduces the usb and dc current limits by 5%/? when the die temperature exceeds +100?. the system load (i sys ) has priority over the charger cur- rent, so input current is first reduced by lowering charge current. if the junction temperature still reaches +120? in spite of charge-current reduction, no input current is drawn from usb and dc; the battery supplies the entire load and sys is regulated below bat by v bsreg . note that this on-chip thermal-limiting circuit is not related to and operates independently from the thermistor input. dc power-ok output ( dok ) as shown in figure 5, the dc power-ok output ( dok ) is an open-drain, active-low output. the dok output pulls low when the voltage from dc to agnd (v dc ) is between v dch (typically 6.9v) and v dcl (typically 4.0v). the dc power-ok circuitry remains active in thermal overload and dc suspend. if the dc power-ok output feature is not required, connect dok to ground or leave disconnected. i v r dclim diset = 2000 15 . r v i diset adptr ? 2000 15 . 500 700 600 800 900 1000 3.0 4.0 4.5 3.5 5.0 5.5 6.0 r diset (k ) i dclim (ma) dc input current limit vs. dc input current-limit resistor pen1 = high figure 4. programming dc current limit r diset (k )i dclim (ma) r diset (k )i dclim (ma) 3.01 997 4.32 694 3.09 971 4.42 679 3.16 949 4.53 662 3.24 926 4.64 647 3.32 904 4.75 632 3.40 882 4.87 616 3.48 862 4.99 601 3.57 840 5.11 587 3.65 822 5.23 574 3.74 802 5.36 560 3.83 783 5.49 546 3.92 765 5.62 534 4.02 746 5.76 521 4.12 728 5.90 508 4.22 711 6.04 497 table 2. dc current limit for standard values of r diset
max8671x pmic with integrated charger and smart power selector for handheld devices 28 ______________________________________________________________________________________ battery charger figure 6 shows the typical li+/li-poly charge profile for the max8671x, and figure 7 shows the battery charger state diagram. with a valid dc and/or usb input, the battery charger initiates a charge cycle when the charger is enabled. it first detects the battery voltage. if the battery voltage is less than the prequalification threshold (3.0v), the charger enters prequalification mode in which the bat- tery charges at 10% of the maximum fast-charge cur- rent while deeply discharged. once the battery voltage rises to 3.0v, the charger transitions to fast-charge mode and applies the maximum charge current. as charging continues, the battery voltage rises until it approaches the battery regulation voltage (selected with bvset) where charge current starts tapering down. when charge current decreases to 4% of the maximum fast-charge current, the charger enters a brief 15s top-off state and then charging stops. if the battery voltage subsequently drops below the battery regulation voltage by v batrchg , charging restarts and the timers reset. the battery charge rate is set by several factors: battery voltage usb/dc input current limit charge setting resistor, r ciset system load (i sys ) die temperature the max8671x automatically reduces charge current to prevent input overload. max8671x also reduces charge current when in thermal regulation (see the thermal limiting and overload protection section for more information). battery regulation voltage (bvset) bvset allows the maximum battery charge voltage to be set to 4.1v, 4.2v, or 4.350v. drive bvset low to set the regulation voltage to 4.1v. connect bvset to vl or leave unconnected to set the regulation voltage to 4.2v. connect bvset to agnd through a 45k to 55k resistor (r bvset ) to set the regulation voltage to 4.350v. r bvset accuracy is not critical. a 51k ?% resistor is acceptable. charge enable input ( cen ) cen is a digital input. driving cen high disables the battery charger. cen does not affect the usb or dc current limit. driving usus high also disables the bat- tery charger when charging from a usb source (pen1 = low). in many systems, there is no need for the system controller (typically a microprocessor (?)) to disable the charger because the max8671x independently manages the charger power path. in these situations, cen can be connected to ground. do not leave cen unconnected. dok v dcl 4.0v rising (typ) 500mv hyst v dch 6.9v rising (typ) 400mv hyst dc usb undervoltage usb overvoltage agnd max8671x figure 5. dc power-ok logic
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 29 cst[1:2] = 11 low 0 i to i chgmax v batprq v batreg prequalification fast-charge (constant current) fast-charge (constant voltage) done top-off cst[1:2] battery charge current battery voltage i pq high-z cst[1:2] = 00 for simplicity, this figure assumes that i sys ~ 0ma figure 6. li+/li-poly charge profile
max8671x pmic with integrated charger and smart power selector for handheld devices 30 ______________________________________________________________________________________ charge status outputs (cst1, cst2) cst1 and cst2 are open-drain charger status outputs. their function is shown in table 3 and figure 7. when the max8671x is used with a ?, pull cst1 and cst2 up to the system logic voltage with resistors to indicate charge status to the ?. alternatively, cst1 and cst2 sink up to 20ma each for led charge indicators. if the charge status output feature is not required, connect cst1 and cst2 to ground or leave them unconnected. charger disabled cst[1:2] = 11 uok and/or dok = 1 i chg = 0ma timer fault cst [1:2] = 10 i chg = 0ma uok and/or dok = 1 timer extend cst [1:2] = 00 (i set x 20%) < i chg < (i chgmax x 50%) thermistor suspend i chg = 0ma cst[1:2] = 01 uok and/or dok = 1 thermistor suspend i chg = 0ma cst[1:2] = 01 uok and/or dok = 1 thermistor suspend i chg = 0ma cst[1:2] = 01 uok and/or dok = 1 i chgmax = x 1.5v r ciset prequalification cst[1:2] = 00 uok and/or dok = 1 i chg = i chgmax /10 top-off cst[1:2] = 11 uok and/or dok = 1 v bat = v batreg done cst[1:2] = 11 uok and/or dok = 1 (v batreg + v batrchg ) < v bat v batreg i chg = 0ma fast-charge cst[1:2] = 00 uok and/or dok = 1 no input power cst [1:2] = 11 uok = 0, dok = 0 i chg = 0ma t > t prequal v bat > 3.0v ic sets timer = 0 v bat < 2.82v ic sets timer = 0 i chg < i chgmax x 53% or v bat = v batreg ic resumes timer i chg < i chgmax x 4% and v bat = 4.2v ic sets timer = 0 i chg > i chgmax x 7% ic sets timer = 0 cen = 0 usus = 0 ic sets timer = 0 t > t fst-chg i chg < i chgmax x 50% and v bat < v batreg ic extends timer by 2x v bat < (v batreg + v batrchg ) ic sets timer = 0 t > 15s thm out of range thm within range thm within range ic resumes timer thm out of range ic suspends timer cen = 1 or usus = 1 usb and dc = invalid usb and/or dc = invalid 2000 any state timer suspend cst [1:2] = 00 i chg < (i chgmax x 20%) i chg < i chgmax x 23% and v bat = v batreg ic resumes timer i chg < i chgmax x 20% and v bat < v batreg ic suspends timer t > 15s thm within range ic resumes timer thm out of range ic suspends timer figure 7. charger state diagram
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 31 charge timer (ct) as shown in figure 7, a fault timer prevents the battery from charging indefinitely. in prequalification and fast- charge modes, the timer is controlled by the capaci- tance at ct (c ct ). the max8671x supports values of c ct from 0.01? to 1?. calculate the prequalification and fast-charge times as follows (table 4, figure 8): when the charger exits fast-charge mode, a fixed 15s top-off mode is entered: while in the constant-current fast-charge mode (figure 6), if the max8671x reduces the battery charge current due to its internal die temperature or large system loads, it slows down the charge timer. this feature elim- inates nuisance charge timer faults. when the battery charge current is between 100% and 50% of its pro- grammed fast-charge level, the fast-charge timer runs at full speed. when the battery charge current is between 50% and 20% of the programmed fast-charge level, the fast-charge timer is slowed by 2x. similarly, when the battery charge current is below 20% of the programmed fast-charge level, the fast-charge timer is paused. the fast-charge timer is not slowed or paused when the charger is in the constant voltage portion of its fast-charge mode (figure 6) where charge current reduces normally. connect ct to agnd to disable the prequalification and fast-charge timers. with the internal timers of the max8671x disabled, an external device, such as a ?, can control the charge time through the cen input. setting the charger currents (ciset) as shown in table 5 and figure 9, a resistor from ciset to ground (r ciset ) sets the maximum fast- charge current (i chgmax ), the charge current in pre- qualification mode (i pq ), and the top-off threshold (i to ). the max8671x supports values of i chgmax from 200ma to 1000ma. select the r ciset as follows: r v i ciset chgmax = 2000 15 . ts to = 15 t c f t c f pq ct fc ct = = 33 015 660 015 min . min . c ct (nf) t pq (min) t fc (min) 100% to 50% t fc (min) 50% to 20% 68 15.0 299 598 100 22.0 440 880 150 33.0 660 1320 220 48.4 968 1936 470 103.4 2068 4136 table 4. charge times vs. c ct cst1 cst2 charging state 0 0 yes prequalification or fast charge 0 1 no thermistor suspend 1 0 no timer fault 11 no no input power or top-off or done table 3. charge status outputs note: cst1 and cst2 are active-low, open-drain outputs. ? indicates that the output device is pulling low. ??indicates that the output is high impedance. charge, prequalification, and top-off current vs. charge setting resistor r ciset (k ) current (ma) 5 10 10 100 1000 1 015 i chgmax i pq i to figure 8. programming charge current
max8671x pmic with integrated charger and smart power selector for handheld devices 32 ______________________________________________________________________________________ determine i chgmax by considering the characteristics of the battery. it is not necessary to limit the charge cur- rent based on the capabilities of the expected ac-to- dc adapter or usb charging input, the system load, or thermal limitations of the pcb. the max8671x automat- ically lowers the charging current as necessary to accommodate these factors. for the selected value of r ciset , calculate i chgmax , i pq , and i to as follows: in addition to setting the charge current, ciset also pro- vides a means to monitor battery charge current. the ciset output voltage tracks the charge current delivered to the battery, and can be used to monitor the charge rate, as shown in figure 9. a 1.5v output indicates the battery is being charged at the maximum set fast-charge current, and 0v indicates no charging. this voltage is also used by the charger control circuitry to set and monitor the battery current. avoid adding capacitance directly to the ciset pin that exceeds 10pf. if filtering of the charge current monitor is necessary, include a resis- tor of 100k or more between ciset and the filter capacitor to preserve charger stability. step-down converters (reg1, reg2, reg3) reg1, reg2, and reg3 are high-efficiency 2mhz cur- rent-mode, step-down converters with adjustable out- puts. each reg1, reg2, and reg3 step-down converter delivers at least 425ma. the step-down regulator power inputs (pv_) must be connected to sys. the step-down regulators operate with v sys from 2.6v to 5.5v. undervoltage lockout ensures that the step-down regulators do not operate with sys below 2.6v (typ). see the enable/disable (en) and sequencing section for how to enable and disable the step-down convert- ers. when enabled, the max8671x gradually ramps each output up during a soft-start time. soft-start elimi- nates input current surges when regulators are enabled. see the pwm section for information about the step- down converters control scheme. i v r ii ii chgmax ciset pq chgmax to chgmax = = = 2000 15 10 4 . % % monitoring the battery charge current with v ciset battery charging current (a) discharging 1.5 0 0 x r ciset 2000 x i bat v ciset = v ciset (v) 2000 1.5v r ciset figure 9. monitoring the battery charge current with the voltage from ciset to agnd r ciset (k )i chgmax (ma) i pq (ma) i to (ma) 3.01 1000 100 40 4.02 746 75 30 4.99 601 60 24 6.04 497 50 20 6.98 430 43 17 8.06 372 37 15 9.09 330 33 13 10.0 300 30 12 11.0 273 27 11 12.1 248 25 10 13.0 231 23 9 14.0 214 21 9 15.0 200 20 8 table 5. ideal charge currents vs. charge setting resistor
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 33 the max8671x uses external resistor-dividers to set the step-down output voltages between 1v and v sys . use at least 10? of bias current in these dividers to ensure no change in the stability of the closed-loop system. to set the output voltage, select a value for the resistor con- nected between fb_ and agnd (r fbl ). the recom- mended value is 100k . next, calculate the value of the resistor connected from fb_ to the output (r fbh ): reg1, reg2, and reg3 are optimized for high, medi- um, and low output voltages, respectively. the highest overall efficiency occurs with v1 set to the highest out- put voltage and v3 set to the lowest output voltage. pwm the max8671x operates in either auto-pwm or forced- pwm modes. at light load, auto pwm switches only as needed to supply the load to improve light-load effi- ciency of the step-down converter. at higher load cur- rents (~100ma), the step-down converter transitions to fixed 2mhz switching. forced pwm always operates with a constant 2mhz switching frequency regardless of the load. this is useful in low-noise applications. permanently connect pwm high for forced-pwm appli- cations or low for auto-pwm applications. do not change pwm on-the-fly. step-down dropout and minimum duty cycle all the step-down regulators are capable of operating in 100% duty-cycle dropout; however, reg1 has been optimized for this mode of operation. during 100% duty-cycle operation, the high-side p-channel mosfet turns on constantly, connecting the input to the output through the inductor. the dropout voltage (v do ) is cal- culated as follows: v do = i load (r p + r l ) where: r p = p-channel power switch r ds(on) r l = external inductor esr the minimum duty cycle for all step-down regulators is 12.5% (typ), allowing a regulation voltage as low as 1v over the full sys operating range. reg3 is optimized for low duty-cycle operation. step-down input capacitors the input capacitor in a step-down converter reduces current peaks drawn from the power source and reduces switching noise in the controller. the imped- ance of the input capacitor at the switching frequency must be less than that of the source impedance of the supply so that high-frequency switching currents do not pass through the input source. the step-down regulator power inputs are critical dis- continuous current paths that require careful bypass- ing. in the pcb layout, place the step-down regulator input bypass capacitors as close as possible to each pair of switching regulator power input pins (pv_ to pg_) to minimize parasitic inductance. if making con- nections to these caps through vias, be sure to use multiple vias to ensure that the layout does not insert excess inductance or resistance between the bypass cap and the power pins. the input capacitor must meet the input ripple current requirement imposed by the step-down converter. ceramic capacitors are preferred due to their low esr and resilience to power-up surge currents. choose the input capacitor so that its temperature rise due to input ripple current does not exceed about +10?. for a step-down dc-dc converter, the maximum input ripple current is half of the output current. this maximum input ripple current occurs when the step-down converter operates at 50% duty factor (v in = 2 x v out ). bypass each step-down regulator input with a 4.7? ceramic capacitor from pv_ to pg_. use capacitors that maintain their capacitance over temperature and dc bias. ceramic capacitors with an x7r or x5r tem- perature characteristic generally perform well. the capacitor voltage rating should be 6.3v or greater. step-down output capacitors the output capacitance keeps output ripple small and ensures control loop stability. the output capacitor must have low impedance at the switching frequency. ceramic, polymer, and tantalum capacitors are suit- able, with ceramic exhibiting the lowest esr and lowest high-frequency impedance. the max8671x requires at least 20? of output capacitance, which is best achieved with two 10? ceramic capacitors in parallel. as the case sizes of ceramic surface-mount capacitors decrease, their capacitance vs. dc bias voltage char- acteristic becomes poor. due to this characteristic, it is possible for 0805 capacitors to perform well while 0603 capacitors of the same value might not. the max8671x requires a nominal output capacitance of 20?; howev- er, after their dc bias voltage derating, the output capacitance must be at least 15?. rr v v fbh fbl out = ? ? ? ? ? ? ? 10 1 .
max8671x pmic with integrated charger and smart power selector for handheld devices 34 ______________________________________________________________________________________ step-down inductor choose the step-down regulator inductance to be 4.7?. the minimum recommended saturation current requirement is 600ma. in pwm mode, the peak induc- tor currents are equal to the load current plus one half of the inductor ripple current. the max8671x works well with physically small inductors. see table 6 for suggested inductors. the peak-to-peak inductor ripple current during pwm operation is calculated as follows: where f s is the 2mhz switching frequency. the peak inductor current during pwm operation is cal- culated as follows: step-down converter output current the three max8671x step-down regulators each pro- vide at least 425ma of output current when using a rec- ommended inductor (table 6). to calculate the maximum output current for a particular application and inductor use the following two-step process (as shown in figure 10): 1) use the following equation to calculate the approxi- mate duty cycle (d): where: v out = output voltage i outtar = target (desired) output current?annot be more than the minimum p-channel current-limit threshold r n = n-channel on-resistance r p = p-channel on-resistance r l = external inductor? esr v in = input voltage?aximum 2) use the following equation to calculate the maximum output current (i outmax ): where: i lim = p-channel current-limit threshold?inimum v out = output voltage d = approximate duty cycle derived from step 1 f = oscillator frequency?inimum l = external inductor? inductance?inimum r n = n-channel on-resistance r l = external inductor? esr i i vd fl rr d fl outmax lim out nl = ? ? ++ ? () () 1 2 1 1 2 d vi rr vi rr out outtar n l in outtar n p = ++ +? () () ii i l peak load pp _ =+ ? 2 i vv v vfl pp out sys out sys s ? = ? () manufacturer series inductance (?) esr ( ) current rating (ma) dimensions (mm) cdrh2d11hp 4.7 190 750 3.0 x 3.0 x 1.2 = 10.8mm 3 sumida cdh2d09 4.7 218 700 3.0 x 3.0 x 1.0 = 9.0mm 3 nr3012 4.7 130 770 3.0 x 3.0 x 1.2 = 10.8mm 3 taiyo yuden nr3010 4.7 190 750 3.0 x 3.0 x 1.0 = 9.0mm 3 vlf3012 4.7 160 740 2.8 x 2.6 x 1.2 = 8.7mm 3 tdk vlf3010 4.7 240 700 2.8 x 2.6 x 1.0 = 7.3mm 3 DE2812C 4.7 130 880 3.0 x 2.8 x 1.2 = 10.8mm 3 toko de2810c 4.7 180 640 3.0 x 2.8 x 1.0 = 8.4mm 3 table 6. suggested inductors
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 35 linear regulators (reg4, reg5) the reg4 and reg5 linear regulators have low quies- cent current, and low output noise. each regulator sup- plies up to 180ma to its load. bypass each ldo output with a 2.2? or greater capacitor to ground. if v4 or v5 is set to less than 1.5v, bypass the output with 3.3? or greater. each linear regulator has an independent power input (pv4 and pv5) with an input voltage range from 1.7v to v sys (v sys can be up to 5.5v). voltages below the input undervoltage lockout threshold (1.6v) are invalid. the regulator inputs can be driven from an efficient low-voltage source, such as a dc-dc output, to opti- mize efficiency (see the following equation). bypass each ldo input with a 1? or greater capacitor to ground: reg5 is intended to power the system usb transceiver circuitry and is only active when usb power is avail- able. reg4 is powered from the battery when power is not available at dc or usb. see the enable/disable (en) and sequencing section for how to enable and disable the linear regulators. when enabled, the linear regulators soft-start by ramp- ing their outputs up to their target voltage in 3ms. soft- start limits the inrush current when the regulators are enabled. the max8671x uses external resistor-dividers to set the ldo output voltages between 0.6v and v pv_ . use at least 10? of bias current in these dividers to ensure no change in the stability of the closed-loop system. to set the output voltage, select a value for the resistor connected between fb_ and agnd (r fbl ). the recom- mended value is 60.4k . next, calculate the value of the resistor connected from fb_ to the output (r fbh ): for reg4, an external 0.01? bypass capacitor from bp to agnd in conjunction with a 150k internal resis- tor creates a 110hz lowpass filter for noise reduction. bp is a high-impedance node and requires a low-leak- age capacitor. for example, a leakage of 40na results in a 1% error. vl linear regulator vl is the output of a 3.3v linear regulator that powers max8671x internal circuitry. vl is internally powered from the higher of usb or dc and automatically powers up when either of these power inputs exceeds approxi- mately 1.5v. when the higher of the dc and usb sup- ply is between 1.5v and 3.3v, vl operates in dropout. vl automatically powers down when both the usb and dc power inputs are removed. bypass vl to agnd with a 0.1? capacitor. vl remains on even when usb and/or dc are in over- voltage or undervoltage lockout, when sys is in under- voltage lockout, and also during thermal faults. vl sources up to 3ma for external loads. if vl is not used for external loads, the max8671x? usb/dc cur- rent limit guarantees compliance with the usb 2.0 input current specifications. if vl is used for external loads, usb/dc currents increase and might exceed the limits outlined in the usb 2.0 specification. for example, if the usb to sys current is limited to 95ma and vl is sourc- ing 3ma, i usb is 98ma. similarly, if the usb input is sus- pended and vl is sourcing 3ma, i usb is 3ma. rr v v fbh fbl out = ? ? ? ? ? ? ? 06 1 . efficiency v v ldo out in to find the maximum output current for reg with v v to v v v l h and r m d vi rr vi rr va va in out l out outtar n l in outtar n p 332531247 20 130 12 0425 012 013 53 0425 012 0 === = = ++ +? = ++ +? .., .,. %, : () () ..(. .) ..(. ? . .) . () () . .( . ) (. ) (. .) (. . ) . (. ) 23 0 249 1 2 1 1 2 0 555 1 2 1 0 249 2 1810 4710 08 1 0 12 0 13 1 0 249 21810 6 6 6 ? = = ? ? ++ ? = ? ? ++ ? ? i i vd fl rr d fl a v hz h hz outmax lim out nl = ? (. .) . 47 10 08 0 482 6 h a figure 10. step-down converter maximum output current example
max8671x pmic with integrated charger and smart power selector for handheld devices 36 ______________________________________________________________________________________ enable/disable (en) and sequencing figures 11, 12, and 13 show how the five max8671x regulators are enabled and disabled. with a valid sys voltage and die temperature, asserting en high enables reg1?eg4. pulling en low disables reg1?eg5. reg5 is intended to power the system usb transceiver circuitry, which is only active when usb power is available. therefore, a valid source must be on either the usb or dc input for reg5 to enable. usbovlo usbuvlo sysok dcovlo dcuvlo 2mhz osc bias & ref 64 cycle delay (32ms) sysok regon usbpok dcpok regon reg3ok reg1ok reg2ok reg4ok pv5ok en ok soft-start reg5 en ok soft-start reg4 en ok soft-start reg2 en ok soft-start reg1 en ok soft-start reg3 reg3ok reg1ok reg2ok reg4ok reg5ok regon regon reg3ok regon reg3ok reg1ok reg2ok pv4ok dt165 dt165 +165 c die temp 4.0v rising 500mv hyst 6.9v rising 400mv hyst 4.0v rising 500mv hyst 6.9v rising 400mv hyst 1.6v rising 100mv hyst 1.6v rising 100mv hyst 2.5v falling 100mv hyst pv4ok pv5ok en sys pv4 pv5 usb dc max8671x figure 11. enable/disable logic
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 37 the vl regulator is not controlled by en. it is powered from the higher of usb or dc and automatically powers up when either of the power inputs exceeds approxi- mately 1.5v. similarly, vl automatically powers down when both the usb and dc power inputs are removed. soft-start/inrush current the max8671x implements soft-start on many levels to control inrush current, to avoid collapsing supply volt- ages, and to fully comply with the usb 2.0 specifica- tions. all usb, dc, and charging functions implement soft-start. the usb and dc nodes only require 4.7? of input capacitance. furthermore, all regulators imple- ment soft-start to avoid transient overload of power inputs (figure 12). v en v out1 v out2 v vl v usb internal discharge resistors v sys v bat v bat t ss5 v uok high-z v dc v out3 v out4 v out5 high-z v dok high-z high-z v bat < v sys < (v usb or v dc ) t ss4 t d3 t ss3 t d2 t ss2 t ss1 t d1 figure 12. enable and disable waveforms
max8671x pmic with integrated charger and smart power selector for handheld devices 38 ______________________________________________________________________________________ active discharge in shutdown each max8671x regulator (reg1?eg5) has an inter- nal 1k resistor that discharges the output capacitor when the regulator is off. the discharge resistors ensure that the load circuitry powers down completely. the internal discharge resistors are connected when a regulator is disabled and when the device is in uvlo with an input voltage greater than 1.0v. with an input voltage less than 1.0v, the internal discharge resistors are not activated. undervoltage and overvoltage lockout usb/dc uvlo undervoltage lockout (uvlo) prevents an input supply from being used when its voltage is below the operat- ing range. when the usb voltage is less than the usb uvlo threshold (4.0v typ), the usb input is discon- nected from sys, and uok goes high impedance. when the dc voltage is less than the dc uvlo thresh- old (4.0v typ), the dc input is disconnected from sys, and dok goes high impedance. in addition, when both usb and dc are in uvlo, the battery charger is dis- abled, and bat is connected to sys through the inter- nal system load switch. reg1?eg4 are allowed to operate from the battery without power at usb or dc. reg5 is intended to power the system usb transceiver circuitry, which is only active when usb power is avail- able. therefore, a valid source must be present on either the usb or dc input for reg5 to enable. unplug event v usb 3.5v high-z unplugging usb with nothing to discharge c usb (v bat = 3.3v). v5 set for 3.3v if v bat 3.4v, v pv5 will regulate to 3.3v if v bat 3.4v, v pv5 will be slightly less than v bat (dropout) v uok v5 5v t ddreg5 = 120 s (typ) rapid discharge until v usb decays to the higher of 3.5v or v bat + 5omv slow discharge as the max8671x draws usb quiescent current figure 13. reg5 disable detail
max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 39 usb/dc ovlo overvoltage lockout (ovlo) prevents an input supply from being used when its voltage exceeds the operat- ing range. both usb and dc withstand input voltages up to 14v. when the usb voltage is greater than the usb ovlo threshold (6.9v typ), the usb input is dis- connected from sys, and uok goes high impedance. when the dc voltage is greater than the dc ovlo threshold (6.9v typ), the dc input is disconnected from sys, and dok goes high impedance. in addition, when both dc and usb are in ovlo, the battery charger is disabled, and bat is connected to sys through the internal system load switch. reg1?eg4 are allowed to operate from the battery when usb and dc are in over- voltage lockout. the vl supply remains active in ovlo. reg5 is intended to power the system usb transceiver circuitry, which is only active when usb power is avail- able. a valid source must be present on either the usb or dc input for reg5 to enable. sys uvlo a uvlo circuit monitors the voltage from sys to ground (v sys ). when v sys falls below v uvlo_sys (2.5v typ), reg1?eg5 are disabled. v uvlo_sys has a 100mv hysteresis. the vl supply remains active in sys uvlo. reg4/reg5 uvlo a uvlo circuit monitors the pv4 and pv5 ldo power inputs. when the pv_ voltage is below 1.6v, it is invalid and the ldo is disabled. thermal limiting and overload protection the max8671x is packaged in a 5mm x 5mm x 0.8mm 40-pin thin qfn. table 7 shows the thermal character- istics of this package. the max8671x has several mechanisms to control junction temperature in the event of a thermal overload. smart power selector thermal-overload protection the max8671x reduces the usb and dc current limits by 5%/? when the die temperature exceeds +100?. the system load (i sys ) has priority over the charger current, so input current is first reduced by lowering charge current. if the junction temperature still reaches +120? in spite of charge-current reduction, no input current is drawn from usb and dc; the battery supplies the entire load and sys is regulated 82mv (v bsreg ) below bat. note that this on-chip thermal-limiting cir- cuit is not related to and operates independently from the thermistor input. regulator thermal-overload shutdown the max8671x disables all regulator outputs (except vl) when the junction temperature rises above +165?, allowing the device to cool. when the junction tempera- ture cools by approximately 15?, the regulators resume the state indicated by the enable input (en) by repeating their soft-start sequence. note that this thermal-overload shutdown is a fail-safe mechanism; proper thermal design should ensure that the junction temperature of the max8671x never exceeds the absolute maximum rating of +150?. battery charger 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. additionally, the charge timers are suspended and charge status indicators report that the charger is in thermistor sus- pend (cst[1:2] = 01). when the thermistor comes back into range, charging resumes and the charge timer continues from where it left off. table 8 shows thm temperature limits for various thermistor material con- stants. if the battery temperature monitor is not required, bias thm midway between v l and agnd with a resistive divider?00k ?% resistors are rec- ommended. biasing thm midway between v l and agnd bypasses this function. single-layer pcb multilayer pcb continuous power dissipation 1777.8mw derate 22.2mw/? above +70? 2857.1mw derate 35.7mw/? above +70? * ja 45?/w 28?/w jc 1.7?/w 1.7?/w table 7. 5mm x 5mm x 0.8mm thin qfn thermal characteristics * ja is specified according to the jesd51 standard.
max8671x pmic with integrated charger and smart power selector for handheld devices 40 ______________________________________________________________________________________ since the thermistor monitoring circuit employs an external bias resistor from thm to vl (r tb in figure 14), any resistance thermistor can be used as long as the value of r tb is equivalent to the thermistor? +25? resistance. for example, with a 10k at +25? thermis- tor, use 10k at r tb , and with a 100k at +25? ther- mistor, use 100k at r tb . the general relation of thermistor resistance to temperature is defined by the following equation: where: r t = the resistance in ohms of the thermistor at tem- perature t in celsius r 25 = the resistance in ohms of the thermistor at +25? = the material constant of the thermistor that typically ranges from 3000k to 5000k t = the temperature of the thermistor in ? that corre- sponds to r t rr e t t = + ? ? ? ? ? ? ? ? ? ? ? ? ? 25 1 273 1 298 thermistor beta (?[k]) 3000 3250 3500 3750 4250 4250 r tb (k ) 101010101010 r tp (k ) open open open open open 120 r ts (k ) short short short short short short resistance at +25? [k ] 101010101010 resistance at +50? [k ] 4.59 4.30 4.03 3.78 3.32 3.32 resistance at 0? [k ] 25.14 27.15 29.32 31.66 36.91 36.91 nominal hot trip temperature [?] 55 53 51 49 46 45 nominal cold trip temperature [?] -3-10250 table 8. trip temperatures for different thermistors t thm agnd esd diode 0.74 x vl 0.284 x vl hot cold temperature suspend vl cen r tb both comparators have 65mv hysteresis r tp r ts t alternate thermistor configuration max8671x figure 14. thermistor input
thm 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 dif- ferent material constant ( ). for example, a +45? hot threshold and 0? cold threshold can be realized by using a 10k thermistor with a of 4250k and connect- ing 120k in parallel. since the thermistor resistance near 0? is much higher than it is near +50?, 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 lowers both the hot and cold thresholds, while lowering r tb raises both thresholds. pcb layout and routing good printed circuit board (pcb) layout is necessary to achieve optimal performance. refer to the max8671 evaluation kit for maxim? recommended layout. use the following guidelines for the best results: use short and wide traces for high-current and dis- continuous current paths. the step-down regulator power inputs are critical discontinuous current paths that require careful bypassing. place the step-down regulator input bypass capacitors as close as possible to each switching regulator power input pair (pv_ to pg_). minimize the area of the loops formed by the step- down converters?dynamic switching currents. the exposed paddle (ep) is the main path for heat to exit the ic. connect ep to the ground plane with thermal vias to allow heat to dissipate from the device. the max8671x regulator feedback nodes are sensi- tive high-impedance nodes. keep these nodes as short as possible and away from the inductors. the thermistor node is high impedance and should be routed with care. make power ground connections to a power ground plane. make analog ground connections to an ana- log ground plane. connect the ground planes at a single point. the reg4 ldo is a high-performance ldo with high psrr and low noise and care should be used in the layout to obtain the high performance. generally, the reg4 ldo is powered from a step- down regulator output, and therefore, its input capacitor should be bypassed to the power ground plane. however, its output capacitor should be bypassed to the analog ground plane. bp is a high impedance node and leakage current into or out of bp can affect the ldo output accuracy. package marking the top of the max8671x package is laser etched as shown in figure 15: ?671xetl?is the product identification code. the full part number is max8671xetl; however, in this case, the ?ax?prefix is omitted due to space limitations. ?ww?is a date code. ??is the last number in the gregorian calendar year. ?w?is the week number in the gregorian calendar. for example: ?01?is the first week of 2008; the week of january 1st, 2008 ?52?is the fifty-second week of 2010; the week of december 27th, 2010. ?aaa?is an assembly code and lot code. ??denotes lead-free packaging and marks the pin 1 location. max8671x pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 41 top view thin qfn 5mm x 5mm x 0.8mm 8671xe tlyww + aaaa figure 15. package marking example chip information process: bicmos
max8671x pmic with integrated charger and smart power selector for handheld devices 42 ______________________________________________________________________________________ max8671x thin qfn 5mm x 5mm x 0.8mm top view 35 36 34 33 12 11 13 dc fb5 pv5 out5 pg2 14 usus pv3 pg3 pg1 vl fb3 diset lx1 pv1 12 bat 4567 27 28 29 30 26 24 23 22 sys pen1 agnd bvset pv4 out4 usb lx3 3 25 37 cst2 bp 38 39 40 uok cst1 pen2 fb4 dok fb2 thm 32 15 fb1 ct 31 16 17 18 19 20 en lx2 pv2 cen pwm 8910 21 ciset + exposed paddle (ep) pin configuration
max8671x package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .) qfn thin.eps pmic with integrated charger and smart power selector for handheld devices ______________________________________________________________________________________ 43
max8671x pmic with integrated charger and smart power selector for handheld devices maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 44 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2007 maxim integrated products is a registered trademark of maxim integrated products. inc. package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .)

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