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1 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 general description the AAT2557 is a fully integrated 500ma battery charger and a 300ma low dropout (ldo) linear regulator. the input voltage range is 4v to 6.5v for the battery charger and 2.7v to 5.5v for the linear regulator, making it ideal for applications operating with single-cell lithium-ion/ polymer batteries. the battery charger is a complete constant current/con - stant voltage linear charger. it offers an integrated pass device, reverse blocking protection, high accuracy cur - rent and voltage regulation, charge status, and charge termination. the charging current is programmable via external resistor from 15ma to 500ma. in addition to these standard features, the device offers over-voltage, current limit, and thermal protection. the linear regulator is designed for fast transient response and good power supply ripple rejection. capable of up to 300ma load current, it includes short- circuit protection and thermal shutdown. the AAT2557 is available in a pb-free, thermally- enhanced tsopjw-14 package and is rated over the -40c to +85c temperature range. features ? battery charger: ? input voltage range: 4v to 6.5v ? programmable charging current up to 500ma ? highly integrated with ? charging device ? reverse blocking diode ? linear regulator: ? 300ma output current ? low dropout: 400mv at 300ma ? fast line and load transient response ? high accuracy: 1.5% ? 70a quiescent current ? short-circuit, over-temperature, and current limit protection ? tsopjw-14 package ? -40c to +85c temperature range applications ? bluetooth? headsets ? cellular and dect phones ? handheld instruments ? mp3 and portable music players ? pdas and handheld computers ? portable media players typical application batt- adp gnd bat iset inldo batt+ AAT2557 adapter/usb input stat en_bat charer enae en_ldo ldo enae set c batter pa bat ste outldobp c outldo c bp outldo c inldo downloaded from: http:///
2 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 pin descriptions pin # symbol function 1 en_ldo enable pin for the linear regulator. when connected to logic low, the regulator is disabled and con - sumes less than 1a of current. when connected to logic high, it resumes normal operation. 2, 8, 12, 13, 14 gnd ground. 3 byp low noise bypass pin. connect a 10nf capacitor between this pin and ground to improve ac ripple rejection and reduce noise. 4 en_bat enable pin for the battery charger. when connected to logic low, the battery charger is disabled and consumes less than 1a of current. when connected to logic high, the charger resumes nor- mal operation. 5 iset charge current set point. connect a resistor from this pin to ground. refer to typical characteristics curves for resistor selection. 6 bat battery charging and sensing. 7 adp input for usb/adapter charger. 9 stat charge status input. open drain status output. 10 outldo linear regulator output. connect a 2.2f capacitor from this pin to ground. 11 inldo linear regulator input voltage. connect a 1f or greater capacitor from this pin to ground. pin configuration tsopjw-14 (top view) 1 2 3 4 5 6 14 13 12 11 10 9 en_ldo gnd byp en_bat iset bat gnd gndgnd inldo outldo stat 7 8 ad pg nd downloaded from: http:///
3 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 absolute maximum ratings 1 symbol description value units v inldo input voltage to gnd 6.0 v v adp adapter voltage to gnd -0.3 to 7.5 v v en en_ldo, en_bat voltage to gnd -0.3 to 6.0 v v x bat, iset, stat voltage to gnd -0.3 to v adp + 0.3 v v byp byp voltage to gnd -0.3 to v inldo + 0.3 v t j junction temperature range -40 to 150 c t a operating temperature range -40 to 85 c t lead maximum soldering temperature (at leads, 10 sec) 300 c thermal information symbol description value units p d maximum power dissipation 625 mw q ja thermal resistance 2 160 c/w 1. stresses above those listed in absolute maximum ratings may cause permanent damage to the device. functional operation at conditions other than the operating conditions specified is not implied. only one absolute maximum rating should be applied at any one time. 2. mounted on an fr4 board. downloaded from: http:///
4 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 electrical characteristics 1 v inldo = v outldo(nom) + 1v for v outldo options greater than 1.5v. i outldo = 1ma, c outldo = 2.2f, c inldo = 1f, c byp = 10nf, t a = -40c to +85c, unless otherwise noted. typical values are t a = 25c. symbol description conditions min typ max units linear regulator v outldo output voltage tolerance i outldo = 1ma to 300ma t a = 25c -1.5 1.5 % t a = -40c to +85c -2.5 2.5 v inldo input voltage v outldo + v doldo 2 5.5 v v doldo dropout voltage 3 i outldo = 300ma 400 600 mv d v out / v outldo * d v inldo line regulation v inldo = v outldo + 1 to 5.0v 0.09 %/v d v outldo(line) dynamic line regulation i outldo = 300ma, v inldo = v outldo + 1 to v outldo + 2, t r / t f = 2s 2.5 mv d v outldo(load) dynamic load regulation i outldo = 1ma to 300ma, t r <5s 60 mv i outldo output current v outldo > 1.2v 300 ma i sc short-circuit current v outldo < 0.4v 600 ma i qldo quiescent current v inldo = 5v; v en_ldo = v in 70 125 a i shdn shutdown current v inldo = 5v; v en_ldo = 0v 1.0 a psrr power supply rejection ratio i outldo =10ma 1khz 65 db 10khz 45 1mhz 43 t sd over-temperature shutdown threshold 145 c t hys over-temperature shutdown hysteresis 12 c e n output noise 50 v rms t c output voltage temperature coeficient 22 ppm/c t en_ldo_dly ldo enable time delay byp open 15 s v en_ldo(l) ldo enable threshold low 0.6 v v en_ldo(h) ldo enable threshold high 1.5 v i en_ldo ldo enable input current v en_ldo = 5.5v 1.0 a 1. the AAT2557 is guaranteed to meet performance specifications over the -40c to +85c operating temperature range and is assured by design, characterization, and correla - tion with statistical process controls. 2. v do is defined as v in - v out when v out is 98% of nominal. 3. for v out < 2.3v, v do = 2.5v - v out . downloaded from: http:///
5 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 electrical characteristics 1 v adp = 5v; t a = -40c to +85c, unless otherwise noted. typical values are t a = 25c. symbol description conditions min typ max units battery chargeroperation v adp adapter voltage range 4.0 6.5 v v uvlo under-voltage lockout (uvlo) rising edge 3.0 4.0 v uvlo hysteresis 150 mv i op operating current charge current = 200ma 0.5 1 ma i shutdown shutdown current v bat = 4.25v, en_bat = gnd 0.3 1 a i leakage reverse leakage current from bat pin v bat = 4v, adp pin open 0.4 2 a voltage regulation v co(reg) output charge voltage regulation 4.158 4.20 4.242 v d v ch /v ch output charge voltage tolerance 0.5 % v min preconditioning voltage threshold 2.85 3.0 3.15 v v rch battery recharge voltage threshold measured from v co(reg) v co(reg) - 0.1 v current regulation i ch_cc charge current programmable range 15 500 ma d i ch_cc /i ch_cc charge current regulation tolerance 10 % v iset iset pin voltage 2 v k i_a current set factor: i ch /i set 800 charging devices r ds(on) charging transistor on resistance v adp = 5.5v 0.9 1.1 w logic control/protection v en_bat(h) battery charger enable threshold high 1.6 v v en_bat(l) battery charger enable threshold low 0.4 v v stat stat pin output low voltage stat pin sinks 4ma 0.4 v i stat stat pin current sink capability 8 ma v ovp battery over-voltage protection threshold 4.4 v i ch_tkl /i ch _cc preconditioning charge current i ch = 100ma 10 % i ch_term /i ch _cc charge termination current 10 % 1. the AAT2557 is guaranteed to meet performance specifications over the -40c to +85c operating temperature range and is assured by design, characterization, and correla - tion with statistical process controls. downloaded from: http:///
6 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 typical characteristics C battery charger r set (k ) i ch (ma) constant charging current vs. set resistor values 1 10 100 1000 11 01 00 1000 charging current vs. battery voltage (v adp = 5v) v bat (v) i ch (ma) 0 100 200 300 400 500 600 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4. 3 r set = 8.06k r set = 5.36k r set = 3.24k r set = 16.2k r set = 31.6k constant output charge voltage regulation vs. adapter voltage v adp (v) v co_reg (v) 4.194 4.196 4.198 4.200 4.202 4.204 4.206 4. 54 .7 55 5.25 5. 55 .7 56 6.25 6.5 r set = 8.06k r set = 31.6k constant output charge voltage regulation vs. temperature (r set = 8.06k ) temperature ( c) v co(reg) (v) 4.17 4.18 4.19 4.20 4.21 4.22 4.23 - 0 - 25 02 55 07 5 100 constant charging current vs. adapter voltage (r set = 8.06k ) v adp (v) i ch (ma) 170 180 190 200 210 220 44 .2 54 .5 4.75 55 .2 55 .5 5.75 66 .25 6.5 v bat = 3.6v v bat = 4v v bat = 3.3v constant charging current vs. temperature (r set = 8.06k ) temperature ( c) i ch (ma) 190 193 195 198 200 203 205 208 210 -50 -25 02 55 07 5 100 downloaded from: http:///
7 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 typical characteristics C battery charger recharging voltage threshold vs. temperature (r set = 8.06k ) temperature ( c) v rch (v) 4.02 4.04 4.06 4.08 4.10 4.12 4.14 4.16 4.18 -5 0- 25 02 55 07 5 100 preconditioning voltage threshold vs. temperature (r set = 8.06k ) temperature ( c) v min (v) 2.97 2.98 2.99 3 3.01 3.02 3.03 -5 0- 25 02 55 07 5 100 preconditioning charge current vs. temperature (r set = 8.06k ) temperature ( c) i trickle (ma) 19.2 19.4 19.6 19.8 20.0 20.2 20.4 20.6 20.8 -50 -25 02 55 07 5 100 preconditioning charge current vs. adapter voltage v adp (v) i trickle (ma) 0 10 20 30 40 50 60 44 .2 4. 44 .6 4. 85 5. 25 .4 5. 65 .8 66 .2 6.4 r set = 8.06k r set = 5.36k r set = 3.24k r set = 16.2k r set = 31.6k operating current vs. temperature (r set = 8.06k ) temperature ( c) i op (a) 300 350 400 450 500 550 -50 -25 02 55 07 5 100 sleep mode current vs. supply voltage (r set = 8.06k ) v adp (v) i sleep (na) 0 100 200 300 400 500 600 700 800 4 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 85 c 25 c -40 c downloaded from: http:///
8 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 typical characteristics C battery charger enable input high voltage vs. adapter voltage (r set = 8.06k ) v adp (v) v en_bat(h) (v) 0.7 0.8 0.9 1 1.1 1.2 44 .2 54 .5 4.75 55 .2 55 .5 5.75 66 .2 56 .5 -40 c 25 c 85 c enable input low voltage vs. adapter voltage (r set = 8.06k ) v adp (v) v en_bat(l) (v) 0.6 0.7 0.8 0.9 1 1.1 44 .2 54 .5 4.75 55 .2 55 .5 5.75 66 .2 56 .5 -40 c 25 c 85 c typical characteristics C ldo regulator enable input high and low voltages vs. input voltage 1.050 1.075 1.100 1.125 1.150 1.175 1.200 1.225 1.250 2. 53 .0 3. 54 .0 4. 55 .0 5.5 input voltage (v) v en_ldo(l) and v en_ldo(h) (v) v en(h) v en(l) dropout voltage vs. temperature 0 60 120 180 240 300 360 420 480 540 -40 -30 -20 -10 01 02 030405 06 07 08 09 0 100 110 120 temperature ( c) dropout voltage (mv) i l = 300ma i l = 150ma i l = 100ma i l = 50ma dropout characteristics 2.0 2.2 2.4 2.6 2.8 3.0 3.2 2. 72 .8 2. 93 .0 3. 13 .2 3.3 i out = 300ma i out = 150ma i out = 100ma i out = 50ma i out = 10ma i out = 0ma input voltage (v) output voltage (v) dropout voltage vs. output current 0 50 100 150 200 250 300 350 400 450 500 05 0 100 150 200 250 300 output current (ma) dropout voltage (mv) 85 c 25 c -40 c downloaded from: http:///
9 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 typical characteristics C ldo regulator ground current vs. input voltage 0 10 20 30 40 50 60 70 80 90 2 2.5 3 3.5 4.5 45 input voltage (v) ground current ( a) i out =0ma i out =10ma i out =50ma i out =150ma i out =300ma quiescent current vs. temperature 0 10 20 30 40 50 60 70 80 90 100 -4 0- 30 -2 0- 10 01 02 0304 05 0607 08 09 0 100 110 120 temperature ( c) quiescent current ( a) output voltage vs. temperature 1.196 1.197 1.198 1.199 1.200 1.201 1.202 1.203 -40 -30 -20 -10 01 02 03 0405 06 07 08 09 0 100 temperature ( c) output voltage (v) ldo initial turn-on response time time (50s/div) input voltage (top) (v) output voltage (bottom) (v) 0 1 2 3 4 5 6 0 1 2 3 ldo turn-on time from enable (v in present) time (5s/div) enable voltage (top) (v) output voltage (bottom) (v) 0 1 2 3 4 0 1 2 3 4 ldo turn-off response time (i out = 100ma) time (5s/div) enable voltage (top) (v) output voltage (bottom) (v) 0 1 2 3 0 5 downloaded from: http:///
10 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 typical characteristics C ldo regulator line transient response 2.98 2.99 3.00 time (100s/div) input voltage (top) (v) 4 5 6 output voltage (bottom) (v) v in v out load transient response (v out = 2.8v) 2.75 2.80 2.85 2.90 time (100s/div) output voltage (top) (v) 0 100 output current (bottom) (ma) v out i out load transient response 300ma (v out = 2.8v) 2.7 2.8 2.9 3.0 time (10s/div) 0 100 200 300 400 v out i out output voltage (top) (v) output current (bottom) (ma) downloaded from: http:///
11 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 functional block diagram reverse blocking v ref constant current over- temperature protection charge control bat uvlo over- current protection tat - et ap ebat bp err amp outlo lo elo v ref - functional description the AAT2557 is a high performance power management ic comprised of a lithium-ion/polymer battery charger and a linear regulator. battery charger the battery charger is designed for single-cell lithium- ion/polymer batteries using a constant current and con - stant voltage algorithm. the battery charger operates from the adapter/usb input voltage range from 4v to 6.5v. the adapter/usb charging current level can be programmed up to 500ma for rapid charging applica - tions. a status monitor output pin is provided to indicate the battery charge state by directly driving one external led. internal device temperature and charging state are fully monitored for fault conditions. fault condition can be one of the following: ? battery over-voltage (ov) ? battery temperature sense hot or cold ? battery charge timer time-out ? chip thermal shutdown in the event of an over-voltage or over-temperature fail - ure, the device will automatically shut down, protecting the charging device, control system, and the battery under charge. other features include an integrated reverse blocking diode and sense resistor. downloaded from: http:///
12 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 linear regulator the advanced circuit design of the linear regulator has been specifically optimized for very fast start-up. this proprietary cmos ldo has also been tailored for supe - rior transient response characteristics. these traits are particularly important for applications that require fast power supply timing. the high-speed turn-on capability is enabled through implementation of a fast-start control circuit which accelerates the power-up behavior of fundamental con - trol and feedback circuits within the ldo regulator. the ldo regulator output has been specifically optimized to function with low-cost, low-esr ceramic capacitors; however, the design will allow for operation over a wide range of capacitor types. the regulator comes with complete short-circuit and ther - mal protection. the combination of these two internal protection circuits gives a comprehensive safety system to guard against extreme adverse operating conditions. the regulator features an enable/disable function. the en_ldo pin is active high and is compatible with cmos logic levels. to assure the ldo regulator will turn on, the en_ldo control level must be greater than 1.5v. the ldo regulator will be disabled when the voltage on the en_ldo pin falls below 0.6v. if the enable function is not needed in a specific application, it may be tied to inldo to keep the ldo regulator in a continuously on state. battery charger under-voltage lockout the AAT2557 has internal circuits for uvlo and power on reset features. if the adp supply voltage drops below the uvlo threshold, the battery charger will suspend charging and shut down. when power is reapplied to the adp pin or the uvlo condition recovers, the system charge control will automatically resume charging in the appropriate mode for the condition of the battery. protection circuitry over-voltage protection when the voltage on the bat pin exceeds the over- voltage protection threshold (v ovp = 4.4v) it is defined as an over-voltage protection event. if this over-voltage condition occurs, the charger control circuitry will shut down the device. the charger will resume normal charg - ing operation after the over-voltage condition is removed. over-temperature protection the AAT2557s battery charger has a thermal protection circuit which will shut down charging functions when the internal die temperature exceeds the preset thermal limit threshold (145c). once the internal die tempera - ture falls below the thermal limit, normal charging operation will resume. the AAT2557s ldo also has an internal thermal protection circuit which will turn on when the device die temperature exceeds 145c. the internal thermal protection circuit will actively turn off the ldo regulator output pass device to prevent the possibility of over temperature damage. the ldo regu - lator output will remain in a shutdown state until the internal die temperature falls back to 12c below the 145c trip point. short-circuit protection the AAT2557s ldo contains an internal short-circuit protection circuit that will trigger when the output load current exceeds the internal threshold limit. under short-circuit conditions, the output of the ldo regulator will be current limited until the short-circuit condition is removed from the output or until the package power dis - sipation exceeds the device thermal limit. the combination and interaction between the short-cir - cuit and thermal protection systems allow the ldo regu - lator to withstand indefinite short-circuit conditions without sustaining permanent damage. downloaded from: http:///
13 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 battery charging operation battery charging commences only after checking several conditions in order to maintain a safe charging environ - ment. the input supply (adp) must be above the mini - mum operating voltage (uvlo) and the enable pin must be high (internally pulled down). when the battery is connected to the bat pin, the charger checks the condi - tion of the battery and determines which charging mode to apply. if the battery voltage is below v min , the charger begins battery pre-conditioning by charging at 10% of the programmed constant current; e.g., if the pro - grammed current is 150ma, then the pre-conditioning current (trickle charge) is 15ma. pre-conditioning is purely a safety precaution for a deeply discharged cell and will also reduce the power dissipation in the internal series mosfet pass device when the input-output volt - age differential is at its highest. pre-conditioning continues until the battery voltage reaches v min (see figure 1). at this point, the charger begins constant-current charging. the current level for this mode is programmed using a single resistor from the iset pin to ground. programmed current can be set from a minimum 15ma up to a maximum of 500ma. constant current charging will continue until the battery voltage reaches the voltage regulation point, v bat and the battery charger begins constant voltage mode. the regulation voltage is factory programmed to a nominal 4.2v and will continue charging until the charging cur - rent has reduced to 10% of the programmed current. after the charge cycle is complete, the pass device turns off and the device automatically goes into a power-sav - ing sleep mode. during this time, the series pass device will block current in both directions, preventing the bat - tery from discharging through the ic. the battery charger will remain in sleep mode, even if the charger source is disconnected, until one of the fol - lowing events occurs: the battery terminal voltage drops below the v rch threshold; the charger en pin is recycled; or the charging source is reconnected. in all cases, the charger will monitor all parameters and resume charging in the most appropriate mode. i ch _c c re ch ar ge ph as e i ch _t kl v uv lo v mi n v co (r eg ) v rc h i ch _t er m wh en v ba t = v co (r eg ) i ch _t er m wh en v ba t = v co (r eg ) co ns ta nt vo lt ag e ch ar ge ph ase (c v) co ns ta nt cu rren t ch ar ge ph ase (c c) tr ic kl e ch ar ge uvlo ba tte ry co ns ta nt vo lt ag e ch ar ge ph as e co ns ta nt cu rre nt ch ar ge ph as e te rm in at io n ph as e te rm in at io n ph as e i ch _c c figure 1: current vs. voltage profile during charging phases. downloaded from: http:///
14 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 battery charging system operation flow chart power on reset power input voltage v adp > v uvlo fault conditions monitoring ov, ot preconditioning test v mi > v at current pase test v cor > v at voltage pase test i at > i ctrm o o es o preconditioning tricle carge constant current carge mode constant voltage carge mode es es es carge copleted carge control o recarge test v rc > v at es o ut down es nale es o downloaded from: http:///
15 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 application informationsoft start / enable the en_bat pin is internally pulled down. when pulled to a logic high level, the battery charger is enabled. when left open or pulled to a logic low level, the battery charger is shut down and forced into the sleep state. charging will be halted regardless of the battery voltage or charging state. when it is re-enabled, the charge con - trol circuit will automatically reset and resume charging functions with the appropriate charging mode based on the battery charge state and measured cell voltage from the bat pin. the ldo is enabled when the en_ldo pin is pulled high. the control and feedback circuits have been optimized for high-speed, monotonic turn-on characteristics. adapter or usb power input constant current charge levels up to 500ma may be programmed by the user when powered from a sufficient input power source. the battery charger will operate from the adapter input over a 4.0v to 6.5v range. programming charge current the fast charge constant current charge level is user programmable with a set resistor placed between the iset pin and ground. the accuracy of the fast charge, as well as the preconditioning trickle charge current, is dominated by the tolerance of the set resistor used. for this reason, a 1% tolerance metal film resistor is recom - mended for the set resistor function. fast charge con - stant current levels from 15ma to 500ma may be set by selecting the appropriate resistor value from table 2. charge status output the AAT2557 provides battery charge status via a status pin. this pin is internally connected to an n-channel open drain mosfet, which can be used to drive an exter - nal led. the status pin can indicate several conditions, as shown in table 1. event description status no battery charging activity off battery charging via adapter or usb port on charging completed off table 1: led status indicator. constant charge current i ch_cc (ma) set resistor value (k w ) 500 3.24 400 4.12 300 5.36 250 6.49 200 8.06 150 10.7 100 16.2 50 31.6 40 38.3 30 53.6 20 78.7 15 105 table 2: r set values. r set (k ) i ch_cc (ma) 1 10 100 1000 11 0 100 1000 figure 2: constant charging current vs. set resistor values. the led should be biased with as little current as neces - sary to create reasonable illumination; therefore, a bal - last resistor should be placed between the led cathode and the stat pin. led current consumption will add to the overall thermal power budget for the device pack - age, hence it is good to keep the led drive current to a minimum. 2ma should be sufficient to drive most low- cost green or red leds. it is not recommended to exceed 8ma for driving an individual status led. downloaded from: http:///
16 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 the required ballast resistor values can be estimated using the following formulas: (v adp - v f(led) ) r 1 = i led example: (5.5v - 2.0 v) r 1 == 1.75k 2ma note: red led forward voltage (v f ) is typically 2.0v @ 2ma. thermal considerations the AAT2557 is offered in a tsopjw-14 package which can provide up to 625mw of power dissipation when it is properly bonded to a printed circuit board and has a maximum thermal resistance of 160c/w. many consid - erations should be taken into account when designing the printed circuit board layout, as well as the placement of the charger ic package in proximity to other heat generating devices in a given application design. the ambient temperature around the ic will also have an effect on the thermal limits of a battery charging appli - cation. the maximum limits that can be expected for a given ambient condition can be estimated by the follow - ing discussion. first, the maximum power dissipation for a given situa - tion should be calculated: (t j(max) - t a ) p d(max) = ja where: p d(max) = maximum power dissipation (w) q ja = package thermal resistance (c/w) t j(max) = maximum device junction temperature (c) [135c] t a = ambient temperature (c) p d = [(v adp - v bat ) i ch + (v adp i op )] + (v inldo - v outldo ) i outldo + v inldo i qldo where: p d = total power dissipation by the device v adp = adp/usb voltage v bat = battery voltage as seen at the bat pin i ch = constant charge current programmed for the application i op = quiescent current consumed by the charger ic for normal operation [0.5ma] v inldo = input voltage as seen at the inldo pin v outldo = output voltage as seen at the outldo pin i outldo = ldo load current i qldo = ldo quiescent current by substitution, we can derive the maximum charge cur - rent before reaching the thermal limit condition (thermal cycling). the maximum charge current is the key factor when designing battery charger applications. (p d(max) - v in i op ) v in - v bat i ch(max) = (t j(max) - t a ) ja v in - v bat i ch(max) = - v in i op in general, the worst condition is the greatest voltage drop across the ic, when battery voltage is charged up to the preconditioning voltage threshold. capacitor selection linear regulator input capacitor an input capacitor greater than 1f will offer superior input line transient response and maximize power sup - ply ripple rejection. ceramic, tantalum, or aluminum electrolytic capacitors may be selected since there is no specific capacitor esr requirement for c inldo . however, for best performance of the ldo regulator at maximum load current output, ceramic capacitors are recommend - ed for c inldo due to their inherent capability over tanta - lum capacitors to withstand input current surges from low impedance sources such as batteries in portable devices. downloaded from: http:///
17 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 battery charger input capacitor in general, it is good design practice to place a decou - pling capacitor between the adp pin and gnd. an input capacitor in the range of 1f to 22f is recommended. if the source supply is unregulated, it may be necessary to increase the capacitance to keep the input voltage above the under-voltage lockout threshold during device enable and when battery charging is initiated. if the adapter input is to be used in a system with an external power supply source, such as a typical ac-to-dc wall adapter, then a c adp capacitor in the range of 10f should be used. a larger input capacitor in this applica - tion will minimize switching or power transient effects when the power supply is hot plugged in. linear regulator output capacitor for proper load voltage regulation and operational stabil - ity, a capacitor is required between out and gnd. the c outldo capacitor connection to the ldo regulator ground pin should be made as directly as practically possible for maximum device performance. since the regulator has been designed to function with very low esr capacitors, ceramic capacitors in the 1.0f to 10f range are rec - ommended for best performance. applications utilizing the exceptionally low output noise and optimum power supply ripple rejection should use 2.2f or greater for c outldo . in low output current applications, where output load is less than 10ma, the minimum value for c outldo can be as low as 0.47f. battery charger output capacitor the AAT2557 only requires a 1f ceramic capacitor on the bat pin to maintain circuit stability. this value should be increased to 10f or more if the battery connection is made any distance from the charger output. if the AAT2557 is to be used in applications where the battery can be removed from the charger, such as with desktop charging cradles, an output capacitor greater than 10f may be required to prevent the device from cycling on and off when no battery is present. bypass capacitor and low noise applications a bypass capacitor pin is provided to enhance the low noise characteristics of the AAT2557 ldo regulator. the bypass capacitor is not necessary for operation of the AAT2557. however, for best device performance, a small ceramic capacitor should be placed between the bypass pin (byp) and the device ground pin (gnd). the value of c byp may range from 470pf to 10nf. for lowest noise and best possible power supply ripple rejection performance, a 10nf capacitor should be used. to practically realize the highest power supply ripple rejection and lowest output noise performance, it is critical that the capacitor connection between the byp pin and gnd pin be direct and pcb traces should be as short as possible. refer to the pcb layout recommendations section of this docu - ment for examples. there is a relationship between the bypass capacitor value and the ldo regulator turn-on and turnoff time. in applications where fast device turn-on and turn-off time are desired, the value of c byp should be reduced. in applications where low noise performance and/or ripple rejection are less of a concern, the bypass capac - itor may be omitted. the fastest device turn-on time will be realized when no bypass capacitor is used. printed circuit board layout considerations for the best results, it is recommended to physically place the battery pack as close as possible to the AAT2557 bat pin. to minimize voltage drops on the pcb, keep the high current carrying traces adequately wide. the input capacitors should connect as closely as possi - ble to adp and inldo. manufacturer part number value (f) voltage rating temp. co. case size murata grm21br61a106ke19 10 10 x5r 0805 murata grm188r60j475ke19 4.7 6.3 x5r 0603 murata grm188r61a225ke34 2.2 10 x5r 0603 murata grm188r60j225ke19 2.2 6.3 x5r 0603 murata grm188r61a105ka61 1.0 10 x5r 0603 murata grm185r60j105ke26 1.0 6.3 x5r 0603 murata grm188f51h103za01 0.01 50 y5v 0603 murata grm155f51h103za01 0.01 50 y5v 0402 table 3: surface mount capacitors. downloaded from: http:///
18 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 figure 3: AAT2557 evaluation board figure 4: AAT2557 evaluation board top side layout. bottom side layout. r2 1.5k r18.06k c34.7f c510nf c42.2f c210f c110f tb2 bat jp1 jp2 7 9 _ 4 1 10 3
11
5 6 2 8 12 13 14 1

4 1 1
figure 5: AAT2557 evaluation board schematic. downloaded from: http:///
19 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 ordering information package marking 1 part number (tape and reel) 2 tsopjw-14 vkxyy AAT2557ito-ct-t1 tsopjw-14 9zxyy AAT2557ito-cw-t1 skyworks green? products are compliant with all applicable legislation and are halogen-free. for additional information, refer to skyworks de?nition of green? , document number sq04-0074. legend voltage code 1.2 e 1.5 g 1.8 i 1.9 y 2.5 n 2.6 o 2.7 p 2.8 q 2.85 r 2.9 s 3.0 t 3.3 w 4.2 c 1. xyy = assembly and date code. 2. sample stock is generally held on part numbers listed in bold . downloaded from: http:///
20 AAT2557 da ta sheet 500ma battery charger and 300ma ldo regulator for portable systems skyworks solutions, inc. ? phone [781] 376-3000 ? fax [781] 376-3100 ? sales@skyworksinc.com ? www.skyworksinc.com 202178a ? skyworks proprietary information ? products and product information are subject to change without notice. ? july 24, 2012 copyright ? 2012 skyworks solutions, inc. all rights reserved. information in this document is provided in connection with skyworks solutions, inc. (skyworks) pr oducts or services. these materials, including the information contained herein, are provided by sky works as a service to its customers and may be used for informational purposes only by the customer. skyworks a ssumes no responsibility for errors or omissions in these materials or the information contained her ein. sky- works may change its documentation, products, services, speciications or product descriptions at any time, without notice. skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for conlicts, incompatibilities, or other dificulties arising from any fut ure changes. no license, whether express, implied, by estoppel or otherwise, is granted to any intellectual prope rty rights by this document. skyworks assumes no liability for any materials, products or informatio n provided here- under, including the sale, distribution, reproduction or use of skyworks products, information or ma terials, except as may be provided in skyworks terms and conditions of sale. the materials, products and information are provided as is without warranty of any kind, whether e xpress, implied, statutory, or otherwise, including fitness for a particular purpose or use, merchantability, performance, quality or non-infringement of any intellectual proper ty right; all such warranties are hereby expressly disclaimed. skyworks does not warrant the accuracy or completeness of the information, text, graphics or other items contained within these materials. skyworks shall not be liable for any damages, in- cluding but not limited to any special, indirect, incidental, statutory, or consequential damages, i ncluding without limitation, lost revenues or lost profits that may result from the use of the materials or information, whether or not the recipient of materials has been advised of the possibility of such damage. skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, o r other equipment in which the failure of the skyworks products could lead to personal injury, death , physical or en- vironmental damage. skyworks customers using or selling skyworks products for use in such applicatio ns do so at their own risk and agree to fully indemnify skyworks for any damages resulting from such improper use or sale. customers are responsible for their products and applications using skyworks products, which may dev iate from published speciications as a result of design defects, errors, or operation of products ou tside of pub- lished parameters or design speciications. customers should include design and operating safeguards to minimize these and other risks. skyworks assumes no liability for applications assistance, custom er product design, or damage to any equipment resulting from the use of skyworks products outside of stated pub lished speciications or parameters. skyworks, the skyworks symbol, and breakthrough simplicity are trademarks or registered trademarks of skyworks solutions, inc., in the united states and other countries. third-party brands and names are for identiication purposes only, and are the property of their respective owners. additional information , including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by refere nce. package information tsopjw-14 2.40 0.10 2.85 0.20 0.40 bsc 0.20 + 0.10 - 0.05 0.15 0.05 0.04 ref 0.45 0.15 2.75 0.25 4 4 1.05 + 0.05 - 0.0 0 1.00 + 0.000 - 0.075 3.05 + 0.05 - 0.10 0.05 + 0.05 - 0.04 to p view side view end view all dimensions in millimeters. downloaded from: http:///

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