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LTC4080X 1 4080xf wireless headsets bluetooth applications portable mp3 players multifunction wristwatches li-ion battery charger with 1.8v buck regulator 500ma standalone li-ion charger with integrated 300ma synchronous buck in 3mm 3mm dfn the LTC4080X is a complete constant-current/constant- voltage linear battery charger for a single-cell 4.2v lithium-ion/polymer battery with an integrated 300ma synchronous buck converter. a 3mm 3mm dfn package and low external component count make the LTC4080X especially suitable for portable applications. furthermore, the LTC4080X is speci? cally designed to work within usb power speci? cations. the ? c ? h ? r ? g pin indicates when charge current has dropped to ten percent of its programmed value (c/10). an internal 4.5 hour timer terminates the charge cycle. the full-featured LTC4080X battery charger also includes automatic recharge and soft-start to limit inrush current. if trickle charging is desired, please see the ltc4080 datasheet. the LTC4080X integrates a synchronous buck converter that is powered from the bat pin. it has an adjustable output voltage and can deliver up to 300ma of load cur- rent. the buck converter also features low-current high- ef? ciency burst mode operation that can be selected by the mode pin. the LTC4080X is available in 10-lead, low pro? le (0.75 mm) 3mm 3mm dfn and 10-lead mse packages. complete linear battery charger with integrated buck converter in 3mm x 3mm dfn package battery charger: constant-current/constant-voltage operation with thermal feedback to maximize charge rate without risk of overheating internal 4.5 hour safety timer for termination charge current programmable up to 500ma with 5% accuracy c/10 charge current detection output 5a supply current in shutdown mode switching regulator: high ef? ciency synchronous buck converter 300ma output current (constant-frequency mode) 2.7v to 4.5v input range (powered from bat pin) 0.8v to v bat output range mode pin selects fixed (2.25mhz) constant-frequency pwm mode or low i cc (23a) burst mode ? operation 2a bat current in shutdown mode applicatio s u features descriptio u typical applicatio u , lt, ltc and ltm are registered trademarks of linear technology corporation. burst mode is a registered trademark of linear technology corporation. all other trademarks are the property of their respective owners. protected by u.s. patents, including 6522118. 500ma 4.2v li-ion/ polymer battery 4.7 f 806 ? 806k c out 4.7 f 4080x ta01a 10pf 1m LTC4080X en_chrg en_buck mode sw fb prog v cc bat v out (1.8v/300ma) 1o h gnd 4.7 f v cc (3.75v to 5.5v) + load current (ma) 0.01 40 efficiency (%) power loss (mw) 60 80 0.1 10 100 1 1000 20 0 100 1 10 100 0.1 0.01 1000 4080x ta01b v bat = 3.8v v out = 1.8v l = 10 h c = 4.7 f efficiency (burst) power loss (burst) efficiency (pwm) power loss (pwm) buck ef? ciency vs load current (v out = 1.8v)
LTC4080X 2 4080xf pin configuration order information lead free finish tape and reel part marking package description temperature range LTC4080Xedd#pbf LTC4080Xemse#pbf LTC4080Xedd#trpbf LTC4080Xemse#trpbf lcvv ltcvw 10-lead (3mm 3mm) dfn 10-lead plastic mse 0c to 70c 0c to 70c consult ltc marketing for parts speci? ed with wider operating temperature ranges. consult ltc marketing for information on non-standard lead based ? nish parts. for more information on lead free part marking, go to: http://www.linear.com/leadfree/ for more information on tape and reel speci? cations, go to: http://www.linear.com/tapeandreel/ v cc , t < 1ms and duty cycle < 1% .............. C 0.3v to 7v v cc steady state ......................................... C 0.3v to 6v bat, ? c ? h ? r ? g .................................................. C 0.3v to 6v ? e ? n ? _ ? c ? h ? r ? g, prog, ? a ? c ? p ? r .................C 0.3v to v cc + 0.3v mode, en_buck .......................... C 0.3v to v bat + 0.3v fb ............................................................... C 0.3v to 2v (note 1) absolute axi u rati gs w ww u bat short-circuit duration ............................ continuous bat pin current ...................................................800ma prog pin current ....................................................2ma junction temperature .......................................... .125c operating temperature range (note 2) .. C 40c to 85c storage temperature range .................. C 65c to 125c top view dd package 10-lead (3mm 3mm) plastic dfn 10 9 6 7 8 4 5 3 2 1 bat v cc en_chrg prog acpr sw en_buck mode fb chrg 11 t jmax = 110c, ja = 43c/w (note 3) exposed pad (pin 11) is gnd, must be soldered to pcb 1 2 3 4 5 bat v cc en_chrg prog acpr 10 9 8 7 6 11 sw en_buck mode fb chrg top view mse package 10-lead plastic msop t jmax = 125c, ja = 40c/w exposed pad (pin 11) is gnd, must be soldered to pcb
LTC4080X 3 4080xf the denotes speci? cations which apply over the full operating tempera- ture range, otherwise speci? cations are at t a = 25c, v cc = 5v, v bat = 3.8v, v ? e ? n ? _ ? c ? h ? r ? g = 0v, v en_buck = v bat , v mode = 0v. (note 2) electrical characteristics symbol parameter conditions min typ max units v cc battery charger supply voltage (note 4) 3.75 5 5.5 v v bat input voltage for the switching regulator (note 5) 2.7 3.8 4.5 v i cc quiescent supply current (charger on, switching regulator off) v bat = 4.5v (forces i bat and i prog = 0), v en_buck = 0 110 300 a i cc_sd supply current in shutdown (both battery charger and switching regulator off) v ? e ? n ? _ ? c ? h ? r ? g = 5v, v en_buck = 0, v cc > v bat v ? e ? n ? _ ? c ? h ? r ? g = 4v, v en_buck = 0, v cc (3.5v) < v bat (4v) 5 2 10 a a i bat_sd battery current in shutdown (both battery charger and switching regulator off) v ? e ? ? n ? _ ? c ? h ? r ? g = 5v, v en_buck = 0, v cc > v bat v ? e ? ? n ? _ ? c ? h ? r ? g = 4v, v en_buck = 0, v cc (3.5v) < v bat (4v) 0.6 2 5a a battery charger v float v bat regulated output voltage i bat = 2ma i bat = 2ma, 4.3v < v cc < 5.5v 4.179 4.158 4.2 4.2 4.221 4.242 v v i bat current mode charge current r prog = 4k; current mode; v en_buck = 0 r prog = 0.8k; current mode; v en_buck = 0 90 475 100 500 110 525 ma ma v uvlo_chrg v cc undervoltage lockout voltage v cc rising v cc falling 3.5 2.8 3.6 3.0 3.7 3.2 v v v prog prog pin servo voltage 0.8k r prog 4k 0.98 1.0 1.02 v v asd automatic shutdown threshold voltage (v cc C v bat ), v cc low to high (v cc C v bat ), v cc high to low 60 15 82 32 100 45 mv mv t ss_chrg battery charger soft-start time 180 s v badbat bad battery threshold voltage 2.9 v v rechrg recharge battery threshold voltage v float C v bat , 0c < t a < 85c 70 100 130 mv v uvcl1, v uvcl2 (v cc C v bat ) undervoltage current limit threshold voltage i bat = 0.9 i chg i bat = 0.1 i chg 180 90 300 130 mv mv t timer charge termination timer 3 4.5 6 hrs recharge time 1.5 2.25 3 hrs low-battery charge time v bat = 2.5v 0.75 1.125 1.5 hrs i c/10 end of charge indication current level r prog = 2k (note 6) 0.085 0.1 0.115 ma/ma t lim junction temperature in constant- temperature mode 115 c r on_chrg power fet on-resistance (between v cc and bat) i bat = 350ma, v cc = 4v 750 m f badbat defective battery detection ? c ? h ? r ? g pulse frequency v bat = 2v 2 hz d badbat defective battery detection ? c ? h ? r ? g pulse frequency duty ratio v bat = 2v 75 % buck converter v fb fb servo voltage 0.78 0.80 0.82 v i fb fb pin input current v fb = 0.85v C50 50 na f osc switching frequency 1.8 2.25 2.75 mhz i bat_nl_cf no-load battery current (continuous frequency mode) no-load for regulator, v ? e ? n ? _ ? c ? h ? r ? g = 5v, l = 10h, c = 4.7f 1.9 ma
LTC4080X 4 4080xf symbol parameter conditions min typ max units i bat_nl_bm no-load battery current (burst mode operation) no-load for regulator, v ? e ? n ? _ ? c ? h ? r ? g = 5v, mode = v bat , l = 10h, c = 4.7f 23 a i bat_slp battery current in sleep mode v ? e ? n ? _ ? c ? h ? r ? g = 5v, mode = v bat , v out > regulation voltage 10 15 20 a v uvlo_buck buck undervoltage lockout voltage v bat rising v bat falling 2.6 2.4 2.7 2.5 2.8 2.6 v v r on_p pmos switch on-resistance 0.95 r on_n nmos switch on-resistance 0.85 i lim_p pmos switch current limit 375 520 700 ma i lim_n nmos switch current limit 700 ma i zero_cf nmos zero current in normal mode 15 ma i peak peak current in burst mode operation mode = v bat 50 100 150 ma i zero_bm zero current in burst mode operation mode = v bat 20 35 50 ma t ss_buck buck soft-start time from the rising edge of en_buck to 90% of buck regulated output 400 s logic v ih input high voltage ? e ? n ? _ ? c ? h ? r ? g, en_buck, mode pin low to high 1.2 v v il input low voltage ? e ? n ? _ ? c ? h ? r ? g, en_buck, mode pin high to low 0.4 v v ol output low voltage ( ? c ? h ? r ? g, ? a ? c ? p ? r) i sink = 5ma 60 105 mv i ih input current high en_buck, mode pins at 5.5v, v bat = 5v C1 1 a i il input current low ? e ? n ? _ ? c ? h ? r ? g, en_buck, mode pins at gnd C1 1 a r ? e ? n ? _ ? c ? h ? r ? g ? e ? n ? _ ? c ? h ? r ? g pin input resistance v ? e ? n ? _ ? c ? h ? r ? g = 5v 1 1.45 3.3 m i ? c ? h ? r ? g ?? c ? h ? r ? g pin leakage current v bat = 4.5v, v ? c ? h ? r ? g = 5v 1a i ? a ? c ? p ? r ? a ? c ? p ? r pin leakage current v cc = 3v, v ? c ? h ? r ? g = 5v 1a note 1: stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. exposure to any absolute maximum rating condition for extended periods may affect device reliability and lifetime. note 2: the LTC4080X is guaranteed to meet performance speci? cations from 0c to 85c. speci? cations over the C40c to 85c operating temperature range are assured by design, characterization and correlation with statistical process controls. note 3: failure to solder the exposed backside of the package to the pc board ground plane will result in a thermal resistance much higher than 43c/w. the denotes speci? cations which apply over the full operating tempera- ture range, otherwise speci? cations are at t a = 25c, v cc = 5v, v bat = 3.8v, v ? e ? n ? _ ? c ? h ? r ? g = 0v, v en_buck = v bat , v mode = 0v. (note 2) electrical characteristics note 4: although the LTC4080X charger functions properly at 3.75v, full charge current requires an input voltage greater than the desired ? nal battery voltage per v uvcl1 speci? cation. note 5: the 2.8v maximum buck undervoltage lockout (v uvlo_buck ) exit threshold must ? rst be exceeded before the minimum v bat speci? cation applies. note 6: i c/10 is expressed as a fraction of measured full charge current with indicated prog resistor.
LTC4080X 5 4080xf v cc supply voltage (v) 4 float voltage (v) 4.20 5.5 4.05 3.95 4.5 5 3.90 3.85 4.25 4.15 4.10 4.00 6 4080 x g03 charge current (ma) 0 4.17 4.18 4.21 4.20 150 4080x g01 4.16 4.15 50 100 200 250 4.14 4.13 4.19 float voltage (v) r prog = 2k temperature ( c) ?50 float voltage (v) 4.195 10 4.180 4.170 ? 30 ? 10 30 4.165 4.160 4.210 4.205 4.200 4.190 4.185 4.175 50 70 90 4080 x g02 temperature ( c) ?50 200 250 100 150 100 0 ?25 50 125 25 75 50 0 charge current (ma) 4080 x g04 v cc = 6v v bat = 3v r prog = 2k thermal control loop in operation charge current (ma) 0 v prog (v) 0.6 0.8 1.0 175 0.4 0.2 0 25 75 125 50 100 150 200 4080 x g05 r prog = 2k temperature ( c) ?50 r ds(on) ( ? ) 0.7 10 0.4 0.2 ? 30 ?10 30 0.1 0 0.9 0.8 0.6 0.5 0.3 50 70 90 4080 x g06 v cc = 4v i bat = 350ma temperature ( c ) ?50 0.50 threshold voltage (v) 0.55 0.65 0.70 0.75 30 0.95 0.60 ?10 ?30 50 70 10 90 0.80 0.85 0.90 4080 x g07 falling rising temperature ( c) 1.0 1.1 1.3 1.4 1.5 1.7 1.2 1.6 4080 x g08 ?50 pulldown resistance (m ? ) 30 ?10 ?30 50 70 10 90 battery regulation (float) voltage vs charge current battery regulation (float) voltage vs temperature battery regulation (float) voltage vs v cc supply voltage charge current vs temperature with thermal regulation (constant-current mode) prog pin voltage vs charge current charger fet on-resistance vs temperature ? e ? n ? _ ? c ? h ? r ? g, en_buck and mode pin threshold voltage vs temperature ? e ? n ? _ ? c ? h ? r ? g pin pulldown resistance vs temperature typical performance characteristics (t a = 25c, v cc = 5v, v bat = 3.8v, unless otherwise speci? ed)
LTC4080X 6 4080xf 20 25 35 15 10 5 0 30 4080 x g17 battery voltage (v) 2.5 buck input current ( a) 4.5 3.0 3.5 4.0 i out = 1ma v out = 1.8v l = 10 h temperature ( c) 0.80 normalized timer period 0.90 1.05 0.85 1.00 0.95 4080 x g10 ?50 30 ?10 ?30 50 70 10 90 battery voltage (v) 2.5 2.26 2.27 2.28 4.0 4080 x g11 2.25 2.24 3.0 3.5 4.5 2.23 2.22 frequency (mhz) temperature ( c) ?60 1.8 frequency (mhz) 1.9 2.0 2.1 2.2 ?20 20 60 100 2.3 2.4 ?40 0 40 80 4080 x g12 v bat = 2.7v v bat = 4.5v v bat = 3.8v load current (ma) 0.01 40 efficiency (%) power loss (mw) 60 80 0.1 10 100 1 1000 20 0 100 1 10 100 0.1 0.01 1000 4080 x g13 v bat = 3.8v v out = 1.8v l = 10 h c = 4.7 f efficiency (burst) power loss (burst) efficiency (pwm) power loss (pwm) battery voltage (v) 2.5 1.780 buck output voltage (v) 1.785 1.790 1.795 1.800 1.805 1.810 3.0 3.5 4.0 4.5 4080 x g14 pwm mode i out = 1ma v out set for 1.8v burst mode operation temperature (?c) ?50 buck output voltage (v) 1.800 1.805 1.810 10 50 1.795 1.790 ?30 ?10 30 70 90 1.785 1.780 4080 x g15 pwm mode burst mode operation i out = 1ma v out set for 1.8v no-load buck input current (burst mode operation) vs battery voltage normalized charge termination time vs temperature buck oscillator frequency vs battery voltage buck oscillator frequency vs temperature buck ef? ciency vs load current (v out = 1.8v) buck output voltage vs battery voltage buck output voltage vs temperature voltage (mv) 70 40 20 10 0 80 60 50 30 4080 x g09 i chrg , i acpr = 5ma temperature ( c ) ?50 30 ?10 ?30 50 70 10 90 ? c ? h ? r ? g and ? a ? c ? p ? r pin output low voltage vs temperature typical performance characteristics (t a = 25c, v cc = 5v, v bat = 3.8v, unless otherwise speci? ed) buck ef? ciency vs load current (v out = 1.5v) load current (ma) 0.01 40 efficiency (%) power loss (mw) 60 80 0.1 10 100 1 1000 20 0 100 1 10 100 0.1 0.01 1000 4080 x g13a v bat = 3.8v v out = 1.5v l = 10 h c = 4.7 f efficiency (burst) power loss (burst) efficiency (pwm) power loss (pwm)
LTC4080X 7 4080xf 2.7 4.2 3 3.6 3.3 3.9 4.5 4080x g24 battery voltage (v) maximum output current (ma) 40 50 60 30 20 0 10 80 70 l = 10 h v out set for 1.8v battery voltage (v) maximum output current (ma) 300 200 100 500 400 2.7 4.2 3 3.6 3.3 3.9 4.5 4080x g23 l = 10 h v out set for 1.8v 20 25 35 15 10 5 0 30 no load input current ( a) l = 10 h c = 4.7 f v out = 1.8v temperature (?c) ?50 10 50 ?30 ?10 30 70 90 4080 x g18 v bat = 4.2v v bat = 3.8v v bat = 2.7v no-load buck input current (burst mode operation) vs temperature buck main switch (pmos) on-resistance vs battery voltage buck main switch (pmos) on-resistance vs temperature buck synchronous switch (nmos) on-resistance vs battery voltage buck synchronous switch (nmos) on-resistance vs temperature maximum output current (pwm mode) vs battery voltage maximum output current (burst mode operation) vs battery voltage 1.0 1.2 0.8 0.6 0.4 0.2 0 4080 x g19 battery voltage (v) 2.5 on-resistance ( ? ) 4.5 5.0 3.0 3.5 4.0 temperature ( c) ?50 10 50 ?30 ?10 30 70 90 4080 x g20 1.0 1.2 0.8 0.6 0.4 0.2 0 on-resistance ( ? ) 4080 x g21 battery voltage (v) 2.5 on-resistance ( ? ) 0.8 1.0 1.2 4.5 5.0 0.6 0.4 0 3.0 3.5 4.0 0.2 4080 x g22 temperature ( c) ?50 10 50 ?30 ?10 30 70 90 on-resistance ( ? ) 0 0.8 1.0 1.2 0.6 0.4 0.2 typical performance characteristics (t a = 25c, v cc = 5v, v bat = 3.8v, unless otherwise speci? ed)
LTC4080X 8 4080xf 200 s/div v out 1v/div v en _ buck 5v/div 4080x g28 0v 0v 50 s/div v out 20mv/div ac coupled i load 250ma/div i = 0 4080x g25 output voltage transient step response (burst mode) charger v prog soft-start output voltage transient step response (pwm mode) output voltage waveform when switching between burst and pwm mode (i load = 10ma) buck v out soft-start (i load = 50ma) 50 s/div v out 50mv/div ac coupled v mode 5v/div 4080x g27 0v 50 s/div v out 20mv/div ac coupled i load 50ma/div 4080x g26 i = 0 50 s/div v prog 200mv/div 4080x g29 v = 0 typical performance characteristics (t a = 25c, v cc = 5v, v bat = 3.8v, unless otherwise speci? ed)
LTC4080X 9 4080xf pi fu ctio s uuu bat (pin 1): charge current output and buck regulator input. provides charge current to the battery and regulates the ? nal ? oat voltage to 4.2v. an internal precision resistor divider from this pin sets the ? oat voltage and is disconnected in charger shutdown mode. this pin must be decoupled with a low esr capacitor for low-noise buck operation. v cc (pin 2): positive input supply voltage. this pin provides power to the battery charger. v cc can range from 3.75v to 5.5v. this pin should be bypassed with at least a 1f capacitor. when v cc is less than 32mv above the bat pin voltage, the battery charger enters shutdown mode. ? e ? n ? _ ? c ? h ? r ? g (pin 3): enable input pin for the battery charger. pulling this pin above the manual shutdown threshold (v ih ) puts the LTC4080X charger in shutdown mode, thus stop- ping the charge cycle. in battery charger shutdown mode, the LTC4080X has less than 10a supply current and less than 5a battery drain current provided the regulator is not running. enable is the default state, but the pin should be tied to gnd if unused. prog (pin 4): charge current program and charge cur- rent monitor pin. connecting a 1% resistor, r prog , to ground programs the charge current. when charging in constant-current mode, this pin servos to 1v. in all modes, the voltage on this pin can be used to measure the charge current using the following formula: i v r bat prog prog = 400 ? a ? c ? p ? r (pin 5): open-drain power supply status out- put. when v cc is greater than the undervoltage lockout threshold (3.6v) and greater than v bat + 82mv, the ? a ? c ? p ? r pin will be pulled to ground; otherwise the pin is high impedance. ? c ? h ? r ? g (pin 6): open-drain charge status output. the charge status indicator pin has three states: pulldown, high impedance state, and pulsing at 2hz. this output can be used as a logic interface or as an led driver. when the battery is being charged, the ? c ? h ? r ? g pin is pulled low by an internal n-channel mosfet. when the charge current drops to 10% of the full-scale current, the ? c ? h ? r ? g pin is forced to a high impedance state. when the battery voltage remains below 2.9v for one quarter of the full charge time, the battery is considered defective, and the ? c ? h ? r ? g pin pulses at a frequency of 2hz with 75% duty cycle. fb (pin 7): feedback pin for the buck regulator. a resistor divider from the regulators output to the fb pin programs the output voltage. servo value for this pin is 0.8v. mode (pin 8): burst mode enable pin. tie this pin high to force the LTC4080X regulator into burst mode operation for all load conditions. tie this pin low to force constant- frequency mode operation for all load conditions. do not ? oat this pin. en_buck (pin 9): enable input pin for the buck regulator. pull this pin high to enable the regulator, pull low to shut down. do not ? oat this pin. sw (pin 10): switch pin for the buck regulator. minimize the length of the metal trace connected to this pin. place the inductor as close to this pin as possible. gnd (pin 11): ground. this pin is the back of the exposed pad package and must be soldered to the pcb for electrical connection and rated thermal performance.
LTC4080X 10 4080xf block diagra w figure 1. LTC4080X block diagram ? + ? + ?+ ?+ 6 mp4 mp3 mp1 x1 x400 v cc r1 r2 charger enable chrg prog 11 gnd 4080x bd 1v prog c1 c4 c5 0.1v v bat + 82mv 3.6v d3 d2 d1 1.22v ?+ ca ma ?+ va 5 acpr 1 10 7 2 bat sw 0.8v l1 v out c out r8 c pl fb counter logic charger oscillator charge control + ? 2.9v bat badbat ? + c3 c2 en_chrg r en 0.82v charger shutdown 3 ? + c6 0.82v enable buck en_buck mode 9 ? + c7 0.82v 8 v cc pwm control and drive ? + 2.25mhz buck oscillator error amp linear battery charger synchronous buck converter mn1 r7 mp2 r prog + ? 115 c t die ta pulse logic 4
LTC4080X 11 4080xf operatio u the LTC4080X is a full-featured linear battery charger with an integrated synchronous buck converter designed primarily for handheld applications. the battery charger is capable of charging single-cell 4.2v li-ion batteries. the buck converter is powered from the bat pin and has a programmable output voltage providing a maximum load current of 300ma. the converter and the battery charger can run simultaneously or independently of each other. battery charger operation featuring an internal p-channel power mosfet, mp1, the battery charger uses a constant-current/constant-voltage charge algorithm with programmable current. charge current can be programmed up to 500ma with a ? nal ? oat voltage of 4.2v 0.5%. the ? c ? h ? r ? g open-drain status output indicates when c/10 has been reached. no blocking diode or external sense resistor is required; thus, the basic charger circuit requires only two external components. the ? a ? c ? p ? r open-drain output indicates if the v cc input voltage, and the difference between v cc and bat, are suf? cient for charging. an internal charge termination timer adheres to battery manufacturer safety guidelines. furthermore, the LTC4080X battery charger is capable of operating from a usb power source. a charge cycle begins when the voltage at the v cc pin rises above 3.6v and approximately 82mv above the bat pin voltage, a 1% program resistor is connected from the prog pin to ground, and the ? e ? n ? _ ? c ? h ? r ? g pin is pulled below the shutdown threshold (v il ). when the bat pin approaches the ? nal ? oat voltage of 4.2v, the battery charger enters constant-voltage mode and the charge current begins to decrease. when the current drops to 10% of the full-scale charge current, an internal comparator turns off the n-channel mosfet driving the ? c ? h ? r ? g pin, and the pin becomes high impedance. an internal thermal limit reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 115c. this feature protects the LTC4080X from excessive temperature and allows the user to push the limits of the power handling capability of a given circuit board without the risk of damaging the LTC4080X or external components. another bene? t of the thermal limit is that charge current can be set according to typical, rather than worst-case, ambient temperatures for a given application with the assurance that the battery charger will automatically reduce the current in worst-case conditions. an internal timer sets the total charge time, t timer (typi- cally 4.5 hours). when this time elapses, the charge cycle terminates and the ? c ? h ? r ? g pin assumes a high impedance state even if c/10 has not yet been reached. to restart the charge cycle, remove the input voltage and reapply it or momentarily force the ? e ? n ? _ ? c ? h ? r ? g pin above v ih . a new charge cycle will automatically restart if the bat pin voltage falls below v rechrg (typically 4.1v). constant-current / constant-voltage / constant-temperature the LTC4080X battery charger uses a unique architecture to charge a battery in a constant-current, constant-volt- age and constant-temperature fashion. figure 1 shows a simpli? ed block diagram of the LTC4080X. three of the ampli? er feedback loops shown control the constant-cur- rent, ca, constant-voltage, va, and constant-temperature, ta modes. a fourth ampli? er feedback loop, ma, is used to increase the output impedance of the current source pair, mp1 and mp3 (note that mp1 is the internal p-channel power mosfet). it ensures that the drain current of mp1 is exactly 400 times the drain current of mp3. ampli? ers ca and va are used in separate feedback loops to force the charger into constant-current or constant- voltage mode, respectively. diodes d1 and d2 provide priority to either the constant-current or constant-voltage loop, whichever is trying to reduce the charge current the most. the output of the other ampli? er saturates low which effectively removes its loop from the system. when in constant-current mode, ca servos the voltage at the prog pin to be precisely 1v. va servos its non-inverting input to 1.22v when in constant-voltage mode and the internal resistor divider made up of r1 and r2 ensures that the battery voltage is maintained at 4.2v. the prog pin volt- age gives an indication of the charge current anytime in the charge cycle, as discussed in programming charge current in the applications information section.
LTC4080X 12 4080xf if the die temperature starts to creep up above 115c due to internal power dissipation, the transconductance ampli? er, ta, limits the die temperature to approximately 115c by reducing the charge current. diode d3 ensures that ta does not affect the charge current when the die temperature is below 115c. in thermal regulation, the prog pin voltage continues to give an indication of the charge current. in typical operation, the charge cycle begins in constant- current mode with the current delivered to the battery equal to 400v/r prog . if the power dissipation of the LTC4080X results in the junction temperature approaching 115c, the ampli? er (ta) will begin decreasing the charge current to limit the die temperature to approximately 115c. as the battery voltage rises, the LTC4080X either returns to full constant-current mode or enters constant-voltage mode straight from constant-temperature mode. battery charger undervoltage lockout (uvlo) an internal undervoltage lockout circuit monitors the v cc input voltage and keeps the battery charger off until v cc rises above 3.6v and approximately 82mv above the bat pin voltage. the 3.6v uvlo circuit has a built-in hysteresis of approximately 0.6v, and the 82mv automatic shutdown threshold has a built-in hysteresis of approximately 50mv. during undervoltage lockout conditions, maximum battery drain current is 5 a and maximum supply current is 10a. undervoltage charge current limiting (uvcl) the battery charger in the LTC4080X includes undervoltage charge current limiting that prevents full charge current until the input supply voltage reaches approximately 300mv above the battery voltage ( v uvcl1 ). this feature is particu- larly useful if the LTC4080X is powered from a supply with long leads (or any relatively high output impedance). see applications information section for further details. defective battery detection at the beginning of a charge cycle, if the battery voltage is below 2.9v for one quarter of the total charge time (1.125 hr), the battery is assumed to be defective, the charge cycle terminates and the ? c ? h ? r ? g output pulses at a frequency of 2hz with a 75% duty cycle. if, for any reason, the battery voltage rises above 2.9v, the charge cycle will be restarted. to restart the charge cycle (i.e., when the dead battery is replaced with a discharged battery less than 2.9v), the charger must be reset by removing the input voltage and reapplying it or temporarily pulling the ? e ? n ? _ ? c ? h ? r ? g pin above the shutdown threshold. battery charger shutdown mode the LTC4080Xs battery charger can be disabled by pulling the ? e ? n ? _ ? c ? h ? r ? g pin above the shutdown threshold (v ih ). in shutdown mode, the battery drain current is reduced to about 2a and the v cc supply current to about 5a provided the regulator is off. when the input voltage is not present, the battery charger is in shutdown and the battery drain current is less than 5a. power supply status indicator ( ? a ? c ? p ? r) the power supply status output has two states: pulldown and high impedance. the pulldown state indicates that v cc is above the undervoltage lockout threshold and at least 82mv above the bat voltage (see undervoltage lockout). when these conditions are not met, the ? a ? c ? p ? r pin is high impedance indicating that the LTC4080X is unable to charge the battery. ? c ? h ? r ? g status output pin the charge status indicator pin has three states: pulldown, pulsing at 2hz (see defective battery detection) and high impedance. the pulldown state indicates that the battery charger is in a charge cycle. a high impedance state indi- cates that the charge current has dropped below 10% of the full-scale current or the battery charger is disabled. when the timer runs out (4.5 hrs), the ? c ? h ? r ? g pin is also forced to the high impedance state. if the battery charger is not in constant-voltage mode when the charge current is forced to drop below 10% of the full-scale current by uvcl, ? c ? h ? r ? g will stay in the strong pulldown state. charge current soft-start the LTC4080Xs battery charger includes a soft-start circuit to minimize the inrush current at the start of a charge cycle. when a charge cycle is initiated, the charge current ramps from zero to full-scale current over a period of approximate- ly 180s. this has the effect of minimizing the transient current load on the power supply during start-up. operatio u
LTC4080X 13 4080xf timer and recharge the LTC4080Xs battery charger has an internal charge termination timer that starts when the input voltage is greater than the undervoltage lockout threshold and at least 82mv above bat, and the battery charger is leaving shutdown. at power-up or when exiting shutdown, the charge time is set to 4.5 hours. once the charge cycle terminates, the battery charger continuously monitors the bat pin voltage using a comparator with a 2ms ? lter time. when the aver- age battery voltage falls below 4.1v (which corresponds to 80%-90% battery capacity), a new charge cycle is initi- ated and a 2.25 hour timer begins. this ensures that the battery is kept at, or near, a fully charged condition and eliminates the need for periodic charge cycle initiations. the ? c ? h ? r ? g output assumes a strong pulldown state dur- ing recharge cycles until c/10 is reached or the recharge cycle terminates. switching regulator operation: the switching buck regulator in the LTC4080X can be turned on by pulling the en_buck pin above v ih . it has two user- selectable modes of operation: constant-frequency (pwm) mode and burst mode operation. the constant-frequency mode operation offers low noise at the expense of ef? ciency whereas the burst mode operation offers higher ef? ciency at light loads at the cost of increased noise, higher output voltage ripple, and less output current. a detailed descrip- tion of different operating modes and different aspects of operation follow. operations can best be understood by referring to the block diagram. constant-frequency (pwm) mode operation the switching regulator operates in constant-frequency (pwm) mode when the mode pin is pulled below v il . in this mode, it uses a current mode architecture including an oscillator, an error ampli? er, and a pwm comparator for excellent line and load regulation. the main switch mp2 (p-channel mosfet) turns on to charge the inductor at the beginning of each clock cycle if the fb pin voltage is less than the 0.8v reference voltage. the current into the inductor (and the load) increases until it reaches the peak current demanded by the error amp. at this point, the main switch turns off and the synchronous switch mn1 (n-channel mosfet) turns on allowing the inductor current to ? ow from ground to the load until either the next clock cycle begins or the current reduces to the zero current (i zero ) level. oscillator : in constant-frequency mode, the switching regulator uses a dedicated oscillator which runs at a ? xed frequency of 2.25mhz. this frequency is chosen to minimize possible interference with the am radio band. error ampli? er : the error ampli? er is an internally com- pensated transconductance (g m ) ampli? er with a g m of 65 mhos. the internal 0.8v reference voltage is compared to the voltage at the fb pin to generate a current signal at the output of the error ampli? er. this cur- rent signal represents the peak inductor current required to achieve regulation. pwm comparator : lossless current sensing converts the pmos switch current signal to a voltage which is summed with the internal slope compensation signal. the pwm comparator compares this summed signal to determine when to turn off the main switch. the switch current sensing is blanked for ~12ns at the beginning of each clock cycle to prevent false switch turn-off. burst mode operation burst mode operation can be selected by pulling the mode pin above v ih . in this mode, the internal oscil- lator is disabled, the error ampli? er is converted into a comparator monitoring the fb voltage, and the inductor current swings between a ? xed i peak (~100ma) and i zero (35ma) irrespective of the load current as long as the fb pin voltage is less than or equal to the reference voltage of 0.8v. once v fb is greater than 0.8v, the control logic shuts off both switches along with most of the circuitry and the regulator is said to enter into sleep mode. in sleep mode, the regulator only draws about 20 a from the bat pin provided that the battery charger is turned off. when the output voltage droops about 1% from its nominal value, the regulator wakes up and the inductor current resumes swinging between i peak and i zero . the output capacitor recharges and causes the regulator to re-enter the sleep state if the output load remains light operatio u
LTC4080X 14 4080xf operatio u enough. the frequency of this intermittent burst operation depends on the load current. that is, as the load current drops further, the regulator turns on less frequently. thus burst mode operation increases the ef? ciency at light loads by minimizing the switching and quiescent losses. however, the output voltage ripple increases to about 2%. to minimize ripple in the output voltage, the current limits for both switches in burst mode operation are reduced to about 20% of their values in the constant-frequency mode. also the zero current of the synchronous switch is changed to about 35ma thereby preventing reverse conduction through the inductor. consequently, the regu- lator can only deliver approximately 67ma of load current while in burst mode operation. any attempt to draw more load cur rent will cause the output voltage to drop out of regulation. current limit to prevent inductor current runaway, there are absolute current limits (i lim ) on both the pmos main switch and the nmos synchronous switch. these limits are internally set at 520ma and 700ma respectively for pwm mode. if the peak inductor current demanded by the error ampli? er ever exceeds the pmos i lim , the error ampli? er will be ignored and the inductor current will be limited to pmos i lim . in burst mode operation, the pmos current limit is reduced to 100ma to minimize output voltage ripple. zero current comparator the zero or reverse current comparator monitors the induc- tor current to the output and shuts off the synchronous recti? er when this current reduces to a predetermined value (i zero ). in ? xed frequency mode, this is set to nega- tive 15ma meaning that the regulator allows the inductor current to ? ow in the reverse direction (from the output to ground through the synchronous recti? er) to a maximum value of 15ma. this is done to ensure that the regulator is able to regulate at very light loads without skipping any cycles thereby keeping output voltage ripple and noise low at the cost of ef? ciency. however, in burst mode operation, i zero is set to positive 35ma meaning that the synchronous switch is turned off as soon as the current through the inductor to the output decreases to 35ma in the discharge cycle. this preserves the charge on the output capacitor and increases the overall ef? ciency at light loads. soft-start the LTC4080X switching regulator provides soft-start in both modes of operation by slowly charging an internal capacitor. the voltage on this capacitor, in turn, slowly ramps the current limits of both switches from a low value to their respective maximum values over a period of about 400 s. the soft-start capacitor is discharged completely whenever the regulator is disabled. short-circuit protection in the event of a short circuit at the output or during start-up, v out will be near zero volts. since the downward slope of the inductor current is ~v out /l, the inductor current may not get a chance to discharge enough to avoid a runaway situation. because the current sensing is blanked for ~12ns at the beginning of each clock cycle, inductor current can build up to a dangerously high level over a number of cycles even if there is a hard current limit on the main pmos switch. this is why the switching regulator in the LTC4080X also monitors current through the synchronous nmos switch and imposes a hard limit on it. if the inductor current through the nmos switch at the end of a discharge cycle is not below this limit, the regulator skips the next charging cycle thereby preventing inductor current runaway. switching regulator undervoltage lockout whenever v bat is less than 2.7v, an undervoltage lock- out circuit keeps the regulator off, preventing unreliable operation. however, if the regulator is already running and the battery voltage is dropping, the undervoltage comparator does not shut down the regulator until v bat drops below 2.5v.
LTC4080X 15 4080xf applicatio s i for atio wu u u battery charger programming charge current the battery charge current is programmed using a single resistor from the prog pin to ground. the charge current is 400 times the current out of the prog pin. the program resistor and the charge current are calculated using the following equations: r v i i v r prog bat bat prog == 400 1 400 1 , the charge current out of the bat pin can be determined at any time by monitoring the prog pin voltage and using the following equation: i v r bat prog prog = 400 stability considerations the LTC4080X battery charger contains two control loops: constant-voltage and constant-current. the constant- voltage loop is stable without any compensation when a battery is connected with low impedance leads. excessive lead length, however, may add enough series inductance to require a bypass capacitor of at least 1 f from bat to gnd. furthermore, a 4.7f capacitor with a 0.2 to 1 series resistor from bat to gnd is required to keep ripple voltage low when the battery is disconnected. in constant-current mode, the prog pin voltage is in the feedback loop, not the battery voltage. because of the additional pole created by prog pin capacitance, capacitance on this pin must be kept to a minimum. with no additional capacitance on the prog pin, the battery charger is stable with program resistor values as high as 25k. however, additional capacitance on this node reduces the maximum allowed program resistor. the pole frequency at the prog pin should be kept above 100khz. therefore, if the prog pin is loaded with a capacitance, c prog , the following equation should be used to calculate the maximum resistance value for r prog : r khz c prog prog 1 2 100 average, rather than instantaneous, battery current may be of interest to the user. for example, when the switching regulator operating in low-current mode is connected in parallel with the battery, the average current being pulled out of the bat pin is typically of more interest than the instantaneous current pulses. in such a case, a simple rc ? lter can be used on the prog pin to measure the average battery current as shown in figure 2. a 10k resistor has been added between the prog pin and the ? lter capacitor to ensure stability. 4080x f02 c filter charge current monitor circuitry r prog LTC4080X prog gnd 10k figure 2. isolating capacitive load on prog pin and filtering dropout operation when the bat pin voltage approaches v out , the duty cycle of the switching regulator approaches 100%. when v bat is approximately equal to v out , the regulator is said to be in dropout. in dropout, the main switch (mp2) stays on continuously with the output voltage being equal to the battery voltage minus the voltage drops across the main switch and the inductor. operatio u global thermal shutdown the LTC4080X includes a global thermal shutdown which shuts off the entire device (battery charger and switch- ing regulator) if the die temperature exceeds 160c. the LTC4080X resumes normal operation once the temperature drops approximately 14c.
LTC4080X 16 4080xf applicatio s i for atio wu u u times improvement over the non-current limited supply power dissipation. usb and wall adapter power although the LTC4080X allows charging from a usb port, a wall adapter can also be used to charge li-ion batter- ies. figure 3 shows an example of how to combine wall adapter and usb power inputs. a p-channel mosfet, mp1, is used to prevent back conducting into the usb port when a wall adapter is present and schottky diode, d1, is used to prevent usb power loss through the 1k pulldown resistor. typically a wall adapter can supply signi? cantly more current than the current-limited usb port. therefore, an n-channel mosfet, mn1, and an extra program resistor can be used to increase the charge current when the wall adapter is present. undervoltage charge current limiting (uvcl) usb powered systems tend to have highly variable source impedances (due primarily to cable quality and length). a transient load combined with such impedance can easily trip the uvlo threshold and turn the battery charger off unless undervoltage charge current limiting is implemented. consider a situation where the LTC4080X is operating under normal conditions and the input supply voltage begins to sag (e.g. an external load drags the input supply down). if the input voltage reaches v uvcl (approximately 300mv above the battery voltage, v uvcl ), undervoltage charge current limiting will begin to reduce the charge current in an attempt to maintain v uvcl between v cc and bat. the LTC4080X will continue to operate at the reduced charge current until the input supply voltage is increased or volt- age mode reduces the charge current further. operation from current limited wall adapter by using a current limited wall adapter as the input sup- ply, the LTC4080X can dissipate signi? cantly less power when programmed for a current higher than the limit of the wall adapter. consider a situation where an application requires a 200ma charge current for a discharged 800mah li-ion battery. if a typical 5v (non-current limited) input supply is avail- able then the peak power dissipation inside the part can exceed 300mw. now consider the same scenario, but with a 5v input supply with a 200ma current limit. to take advantage of the supply, it is necessary to program the LTC4080X to charge at a current greater than 200ma. assume that the LTC4080X charger is programmed for 300ma (i.e., r prog = 1.33k ) to ensure that part tolerances maintain a programmed current higher than 200ma. since the battery charger will demand a charge current higher than the current limit of the input supply, the supply voltage will collapse to the battery voltage plus 200ma times the on-resistance of the internal pfet. the on-resistance of the battery charger power device is approximately 0.75 with a 5v supply. the actual on-resistance will be slightly higher due to the fact that the input supply will have col- lapsed to less than 5v. the power dissipated during this phase of charging is approximately 30mw. that is a ten v cc mp1 mn1 1k 2k 1.33k 1 i chg 2 d1 4 li-ion battery system load 4080x f03 LTC4080X bat usb power (200ma) 5v wall adapter (300ma) prog + figure 3. combining wall adapter and usb power power dissipation the conditions that cause the LTC4080X battery charger to reduce charge current through thermal feedback can be approximated by considering the total power dissipated in the ic. for high charge currents, the LTC4080X power dissipation is approximately: pvv i p d cc bat bat d buck =? () + _ where p d is the total power dissipated within the ic, v cc is the input supply voltage, v bat is the battery voltage, i bat is the charge current and p d_buck is the power dissipation due to the regulator. p d_buck can be calculated as: pvi d buck out out _ =? ? ? ? ? ? ? 1 1
LTC4080X 17 4080xf applicatio s i for atio wu u u where v out is the regulated output of the switching regulator, i out is the regulator load and is the regulator ef? ciency at that particular load. it is not necessary to perform worst-case power dissipa- tion scenarios because the LTC4080X will automatically reduce the charge current to maintain the die temperature at approximately 115c. however, the approximate ambi- ent temperature at which the thermal feedback begins to protect the ic is: t a = 115c C p d ja t a = 115c C (v cc C v bat ) ? i bat ? ja if the regulator is off. example: consider the extreme case when an LTC4080X is operating from a 6v supply providing 250ma to a 3v li-ion battery and the regulator is off. the ambient tem- perature above which the LTC4080X will begin to reduce the 250ma charge current is approximately: t a = 115c C (6v C 3v) ? (250ma) ? 43c/w t a = 115c C 0.75w ? 43c/w = 115c C 32.25c t a = 82.75c if there is more power dissipation due to the regulator, the thermal regulation will begin at a somewhat lower temperature. in the above circumstances, the LTC4080X can be used above 82.75c, but the charge current will be reduced from 250ma. the approximate current at a given ambient temperature can be calculated: i ct vv bat a cc bat ja = ? ? () 115 using the previous example with an ambient temperature of 85c, the charge current will be reduced to approxi- mately: i cc vv cw c ca bat = ? ? () = = 115 85 63 43 30 129 2 / / 3 32 6 .ma furthermore, the voltage at the prog pin will change proportionally with the charge current as discussed in the programming charge current section. v cc bypass capacitor many types of capacitors can be used for input bypassing; however, caution must be exercised when using multi-layer ceramic capacitors. because of the self-resonant and high q characteristics of some types of ceramic capacitors, high voltage transients can be generated under some start-up con- ditions, such as connecting the battery charger input to a live power source. adding a 1 series resistor in series with an x5r ceramic capacitor will minimize start-up voltage transients. for more information, refer to application note 88. switching regulator setting the buck converter output voltage the LTC4080X regulator compares the fb pin voltage with an internal 0.8v reference to generate an error signal at the output of the error ampli? er. a voltage divider from v out to ground (as shown in the block diagram) programs the output voltage via fb using the formula: vv r r out =+ ? ? ? ? ? ? 08 1 7 8 . keeping the current low (<5a) in these resistors maxi- mizes ef? ciency, but making them too low may allow stray capacitance to cause noise problems and reduce the phase margin of the error amp loop. to improve the frequency response, a phase-lead capacitor (c pl ) of approximately 10pf can be used. great care should be taken to route the fb line away from noise sources, such as the inductor or the sw line. inductor selection the value of the inductor primarily determines the cur- rent ripple in the inductor. the inductor ripple current i l decreases with higher inductance and increases with higher v in or v out : ? i v fl v v l out out in =? ? ? ? ? ? ? 0 1 accepting larger values of i l allows the use of low inductances, but results in higher output voltage ripple, greater core losses, and lower output current capability. a
LTC4080X 18 4080xf applicatio s i for atio wu u u reasonable starting point for setting ripple current is i l =0.3 ? i lim , where i lim is the peak switch current limit. the largest ripple current occurs at the maximum input voltage. to guarantee that the ripple current stays below a speci? ed maximum, the inductor value should be chosen according to the following equation: l v fi v v out l out in max ? ? ? ? ? ? ? ? ? () 0 1 ? for applications with v out = 1.8v, the above equation suggests that an inductor of at least 6.8h should be used for proper operation. many different sizes and shapes of inductors are available from numerous manufacturers. to maximize ef? ciency, choose an inductor with a low dc resistance. keep in mind that most inductors that are very thin or have a very small volume typically have much higher core and dcr losses and will not give the best ef? ciency. also choose an inductor with a dc current rating at least 1.5 times larger than the peak inductor current limit to ensure that the inductor does not saturate during nor- mal operation. to minimize radiated noise, use a toroid, or shielded pot core inductors in ferrite or permalloy materials. table 1 shows a list of several inductor manu- facturers. table 1. recommended surface mount inductor manufacturers coilcraft www.coilcraft.com sumida www.sumida.com murata www.murata.com toko www.tokoam.com input and output capacitor selection since the input current waveform to a buck converter is a square wave, it contains very high frequency components. it is strongly recommended that a low equivalent series resistance (esr) multilayer ceramic capacitor be used to bypass the bat pin which is the input for the converter. tantalum and aluminum capacitors are not recommended because of their high esr. the value of the capacitor on bat directly controls the amount of input voltage ripple for a given load current. increasing the size of this capacitor will reduce the input ripple. to prevent large v out voltage steps during transient load conditions, it is also recommended that a ceramic capacitor be used to bypass v out . a typical value for this capacitor is 4.7f. multilayer ceramic chip capacitors (mlcc) typically have exceptional esr performance. mlccs combined with a carefully laid out board with an unbroken ground plane will yield very good performance and low emi emissions. there are several types of ceramic capacitors with consider- ably different characteristics. y5v ceramic capacitors have apparently higher packing density but poor performance over their rated voltage or temperature ranges. under given voltage and temperature conditions, x5r and x7r ceramic capacitors should be compared directly by case size rather than speci? ed value for a desired minimum capacitance. some manufacturers provide excellent data on their websites about achievable capacitance. table 2 shows a list of several ceramic capacitor manufacturers. table 2. recommended ceramic capacitor manufacturers taiyo yuden www.t-yuden.com avx www.avxcorp.com murata www.murata.com tdk www.tdk.com board layout considerations to be able to deliver maximum charge current under all conditions, it is critical that the exposed metal pad on the backside of the LTC4080Xs package has a good thermal contact to the pc board ground. correctly soldered to a 2500mm 2 double-sided 1 oz. copper board, the LTC4080X has a thermal resistance of approximately 43c/w. failure to make thermal contact between the exposed pad on the backside of the package and the copper board will result in thermal resistances far greater than 43c/w. furthermore due to its high frequency switching circuitry, it is imperative that the input capacitor, bat pin capaci- tor, inductor, and the output capacitor be as close to the LTC4080X as possible and that there is an unbroken ground plane under the LTC4080X and all of its high frequency components.
LTC4080X 19 4080xf information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. package descriptio u dd package 10-lead plastic dfn (3mm 3mm) (reference ltc dwg # 05-08-1699) 3.00 0.10 (4 sides) 4. dimensions of exposed pad on bottom of package do not include mold flash. mold flash, if present, shall not exceed 0.15mm on any side 5. exposed pad shall be solder plated 6. shaded area is only a reference for pin 1 location on the top and bottom of package note: 1. drawing to be made a jedec package outline m0-229 variation of (weed-2). check the ltc website data sheet for current status of variation assignment 2. drawing not to scale 3. all dimensions are in millimeters 0.38 0.10 bottom view?exposed pad 1.65 0.10 (2 sides) 0.75 0.05 r = 0.115 typ 2.38 0.10 (2 sides) 1 5 10 6 pin 1 top mark (see note 6) 0.200 ref 0.00 ? 0.05 (dd10) dfn 1103 0.25 0.05 2.38 0.05 (2 sides) recommended solder pad pitch and dimensions 1.65 0.05 (2 sides) 2.15 0.05 0.50 bsc 0.675 0.05 3.50 0.05 package outline 0.25 0.05 0.50 bsc msop (mse) 0603 0.53 0.152 (.021 .006) seating plane 0.18 (.007) 1.10 (.043) max 0.17 ? 0.27 (.007 ? .011) typ 0.127 0.076 (.005 .003) 0.86 (.034) ref 0.50 (.0197) bsc 12 3 45 4.90 0.152 (.193 .006) 0.497 0.076 (.0196 .003) ref 8 9 10 10 1 7 6 3.00 0.102 (.118 .004) (note 3) 3.00 0.102 (.118 .004) (note 4) note: 1. dimensions in millimeter/(inch) 2. drawing not to scale 3. dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.152mm (.006") per side 4. dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.152mm (.006") per side 5. lead coplanarity (bottom of leads after forming) shall be 0.102mm (.004") max 0.254 (.010) 0 ? 6 typ detail ?a? detail ?a? gauge plane 5.23 (.206) min 3.20 ? 3.45 (.126 ? .136) 0.889 0.127 (.035 .005) recommended solder pad layout 0.305 0.038 (.0120 .0015) typ 2.083 0.102 (.082 .004) 2.794 0.102 (.110 .004) 0.50 (.0197) bsc bottom view of exposed pad option 1.83 0.102 (.072 .004) 2.06 0.102 (.081 .004) mse package 10-lead plastic msop (reference ltc dwg # 05-08-1664)
LTC4080X 20 4080xf linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 2007 lt 0307 ? printed in usa part number description comments battery chargers ltc3550 dual input usb/ac adapter li-ion battery charger with adjustable output 600ma buck converter synchronous buck converter, ef? ciency: 93%, adjustable output: 600ma, charge current: 950ma programmable, usb compatible, automatic input power detection and selection ltc3550-1 dual input usb/ac adapter li-ion battery charger with 600ma buck converter synchronous buck converter, ef? ciency: 93%, output: 1.875v at 600ma, charge current: 950ma programmable, usb compatible, automatic input power detection and selection ltc4054 standalone linear li-ion battery charger with integrated pass transistor in thinsot tm thermal regulation prevents overheating, c/10 termination ltc4061 standalone li-ion charger with thermistor interface 4.2v, 0.35% float voltage, up to 1a charge current, 3mm 3mm dfn package ltc4061-4.4 standalone li-ion charger with thermistor interface 4.4v (max), 0.4% float voltage, up to 1a charge current, 3mm 3mm dfn package ltc4062 standalone linear li-ion battery charger with micropower comparator up to 1a charge current, charges from usb port, thermal regulation 3mm 3mm dfn package ltc4063 li-ion charger with linear regulator up to 1a charge current, 100ma, 125mv ldo, 3mm 3mm dfn package ltc4080 standalone 500ma charger with 300ma synchronous buck for 1-cell li-ion/polymer batteries; trickle charge; timer termination +c/10; thermal regulation, buck output: 0.8v to v bat , buck input: 2.7v to 5.5v, 3mm 3mm dfn-10 package power management ltc3405/ltc3405a 300ma (i out ), 1.5mhz, synchronous step-down dc/dc converter 95% ef? ciency, v in : 2.7v to 6v, v out = 0.8v, i q = 20a, i sd < 1a, thinsot package ltc3406/ltc3406a 600ma (i out ), 1.5mhz, synchronous step-down dc/dc converter 95% ef? ciency, v in : 2.5v to 5.5v, v out = 0.6v, i q = 20a, i sd < 1a, thinsot package ltc3411 1.25a (i out ), 4mhz, synchronous step-down dc/dc converter 95% ef? ciency, v in : 2.5v to 5.5v, v out = 0.8v, i q = 60a, i sd < 1a, ms package ltc3440 600ma (i out ), 2mhz, synchronous buck-boost dc/dc converter 95% ef? ciency, v in : 2.5v to 5.5v, v out = 2.5v, i q = 25a, i sd < 1a, ms package ltc4411/ltc4412 low loss powerpath tm controller in thinsot automatic switching between dc sources, load sharing, replaces oring diodes ltc4413 dual ideal diode in dfn 2-channel ideal diode oring, low forward on-resistance, low regulated forward voltage, 2.5v v in 5.5v thinsot and powerpath are trademarks of linear technology corporation. related parts typical applicatio u li-ion battery charger with 1.5v buck regulator d1 500ma c bat 4.7 f r3 510 ? r prog 806 ? r2 806k c out 4.7 f 4080x ta02 c pl 10pf r1 715k LTC4080X v cc acpr en_chrg en_buck mode bat chrg sw fb prog v out (1.5v/300ma) l1, 1o h* gnd d2 *coilcraft lpo1704-103m r4, 510 ? c in 4.7 f v cc (3.75v to 5.5v) 4.2v li-ion battery + buck ef? ciency vs load current (v out = 1.5v) load current (ma) 0.01 40 efficiency (%) power loss (mw) 60 80 0.1 10 100 1 1000 20 0 100 1 10 100 0.1 0.01 1000 4080x g13 v bat = 3.8v v out = 1.5v l = 10 h c = 4.7 f efficiency (burst) power loss (burst) efficiency (pwm) power loss (pwm)

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