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1 LTC 4056 is a low cost, single-cell, constant-current/constant-voltage Li-Ion battery charger controller with aprogrammable termination timer. When combined with afew external components, the LTC4056 forms a very smallstandalone charger for single cell lithium-ion current and charge time are set externally with asingle resistor and capacitor, respectively. The LTC4056charges to a final float voltage accurate to Manualshutdown is accomplished by grounding the TIMER/SHDN pin, while removing input power automatically putsthe LTC4056 into a sleep mode. Both the shutdown andsleep modes drain near zero current from the battery; theshutdown mode reduces supply current to 40 output driver is both current limited and thermallyprotected to prevent operating outside of safe limits. Noexternal blocking diode or sense resistor is required. TheLTC4056 also includes low battery charge conditioning(trickle charging), undervoltage charge current limiting,automatic recharge and a charge status LTC4056 is available in a low profile (1mm) 8-leadSOT-23 (ThinSOTTM) TelephonesnHandheld ComputersnDigital CamerasnCharging Docks and CradlesnLow Cost and Small Size Chargers, LTC and LT are registered trademarks of Linear Technology Li-Ion Charger with TerminationnProgrammable Termination TimernNo Sense Resistor or Blocking Diode RequirednSuitable for USB-Powered ChargingnUndervoltage Charge Current LimitingnPreset Charge Voltage with AccuracynProgrammable Charge Current.

2 200mA to 700mAnAutomatic Recharge with Shortened Charge CyclenSelf-Protection for Overcurrent/Overtemperaturen40 A Supply Current in Shutdown ModenNegligible Battery Drain Current in ShutdownnLow Battery Charge Conditioning (Trickle Charging)nCHRG Status Output including AC PresentnPCB Total Solution Area only 75mm2 (700mA)nLow Profile (1mm) SOT-23 PackageLinear Li-Ion Chargerwith Termination in TO Li-Ion1 F1 +ThinSOT is a trademark of Linear Technology (V) (mA) CHARGECURRENT LIMITINGUNDERVOLTAGELOCKOUT AT = 4 VRPROG = = 700mAINPUT Z = 100m VIN Undervoltage ChargeCurrent LimitingDESCRIPTIOUFEATURESAPPLICATIO SUTYPICAL PARTNUMBERTS8 PARTMARKINGTJMAX = 125 C, JA = 120 C/W TO 200 C/WDEPENDING ON PC BOARD LAYOUTC onsult LTC Marketing for parts specified with wider operating temperature AXI U RATI GSWWWUPACKAGE/ORDER I FOR ATIOUUW(Note 1)ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25 C.

3 VCC = Supply Voltage (VCC) .. to 10 VBAT, CHRG .. to 10 VDRIVE, PROG, TIMER/SHDN .. to (VCC + )Output Current (ISENSE) .. 900mAShort-Circuit Duration (BAT, ISENSE) .. ContinuousJunction Temperature .. 125 COperating Ambient Temperature Range(Note 2) .. 40 C to 85 CStorage Temperature Range .. 65 C to 150 CLead Temperature (Soldering, 10 sec) .. 300 C1234 VCCISENSEDRIVEGND8765 CHRGBATPROGTOP VIEWTS8 PACKAGE8-LEAD PLASTIC SOT-23 TIMER/SHDNSYMBOLPARAMETERCONDITIONSMINTY PMAXUNITSVCC SupplyVCCI nput Supply Voltage (Note 3) VCC Supply CurrentVBAT = (Forces IDRIVE = 0)IPROG = 200 A (RPROG = 5k)l400600 AISHDNVCC Supply Current in Manual ShutdownVTIMER/SHDN = 0V4060 AIBMSB attery Drain Current inVTIMER/SHDN = 0Vl 101 AManual Shutdown (Note 4)IBSLB attery Drain Current inVCC = 0Vl 101 ASleep Mode (Note 5)VUVLOIU ndervoltage Rising ThresholdVCC Falling ThresholdVCC HysteresisVUVLOI-VUVLOD50mVVUVCLU ndervoltage Charge Current Limit Charge Current to UVLO Threshold Marginl90170250mVCharging PerformanceVFLOATO utput Float Voltage inIBAT = Voltage ModeIBAT = 10mA, VCC Full-Scale Current inRPROG = 5k, VCC ,137183228mAConstant Current ModePNP Beta > 50, 0 C TA 85 CRPROG = , VCC ,590640690mAPNP Beta > 50, 0 C TA 85 CIDSINKD rive Output CurrentVDRIVE = 3Vl30mAITRIKLT rickle Charge CurrentVBAT = 2V, RPROG = 5k5710mAVBAT = 2V, RPROG = Charge Threshold VoltageVBAT VTRIKLT rickle Charge Hysteresis Voltage457095mVVPROG1 PROG Pin VoltageRPROG = 5k (IPROG = 200 A) Pin VoltageRPROG = (IPROG = 700 A) CHARACTERISTICSThe l denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25 C.

4 VCC = VRECHRGR echarge Threshold VoltageVFLOAT VRECHRG, VBAT > VTRIKL,100150200mVCharge Termination Timer ExpiredTTIMERTIMER/SHDN AccuracyCTIMER = 1 F RPROG = Manual ControlVMSDTM anual Shutdown Threshold VoltageVTIMER/SHDN Shutdown Hysteresis VoltageVTIMER/SHDN Decreasing5075125mVISHDNTIMER/SHDN Pin Pull-up CurrentVTIMER/SHDN = 0V 10 7 4 AProtectionIDSHRTD rive Output Short-Circuit Current LimitVDRIVE = VCCl3065130mAIPSHRTPROG Pin Short-Circuit Current LimitVPROG = OutputICHRGCHRG Pin Weak Pull-Down CurrentVCHRG = 1V, VTIMER/SHDN = 0V61218 AVCHRGCHRG Output Low VoltageICHRG = 1: Absolute Maximum Ratings are those values beyond which the lifeof a device may be 2: The LTC4056E is guaranteed to meet performance specificationsfrom 0 C to 70 C ambient temperature range. Specifications over the 40 C to 85 C operating ambient temperature range are assured bydesign, characterization and correlation with statistical process 3: Although the LTC4056 will operate with input voltages as low , charging will not begin until VCC exceeds 4: Assumes that the external PNP pass transistor has negligible B-Creverse-leakage current when the collector is biased at (VBAT) and thebase is biased at 5V (VCC).

5 Note 5: Assumes that the external PNP pass transistor has negligible B-Ereverse-leakage current when the emitter is biased at 0V (VCC) and thebase is biased at (VBAT).TYPICAL PERFOR A CE CHARACTERISTICS UWFloat Voltage vs Temperature andSupply VoltageTEMPERATURE ( C) 50 VFLOAT (V) = 10mAPNP = FZT749 VCC = = (mA)0 FLOAT VOLTAGE (V) G02 = 5 VTA = 25 CPNP = FZT749 RPROG = ( C) 50 IBAT (mA) G03200190 2505018518022021020519575100125 RPROG = = FZT749 VCC = = Voltage vs IBATIBAT vs Temperature andSupply PERFOR A CE CHARACTERISTICS UWIBAT vs Temperature andSupply VoltageIBAT vs VBATT imer Error vs TemperatureTEMPERATURE ( C) 50670 IBAT (mA)680690700710730 G0475100720 RPROG = = FZT749 VCC = = (V)0 IBAT (mA) G052001000124600700800 VCC = 5 VTA = 25 CPNP = PIN MUST BEDISCONNECTEDAND SET AND TOFORCE CC MODEIN THIS ( C) 50 5 TIMER ERROR (%) 4 2 G06 3341 2525100125 VCC = 5 VRPROG = Pin Pull-Up Currentvs Temperature and Supply VoltageTEMPERATURE ( C) 50 ISHDN ( A)

6 G0764 2505010012520 VTIMER/SHDN = 0 VVCC = = Pin Weak Pull-Down Currentvs Temperature and VCHRGTEMPERATURE ( C) 505 ICHRG ( A)101520 G0875100125 VTIMER/SHDN = 0 VVCC = 5 VVCHRG = = 1 VCHRG Pin Output Low Voltagevs TemperaturePROG Pin Voltagevs Temperature and RPROGTEMPERATURE ( C) 50 VPROG (V) G1075100125 VCC = 5 VRPROG = = ( C) (V) G0975100 VBAT = 0 VICHRG = 10mAVCC = (Pin 6): Battery Voltage Sense Input. A precisioninternal resistor divider sets the final float voltage on thispin. This divider is disconnected in the manual shutdownor sleep mode. No bypass capacitance is needed on thispin for stable operation when a battery is present. How-ever, any low ESR capacitor exceeding 22 F on this pinshould be decoupled with to 1 resistor. Without abattery, a minimum bypass capacitance of F series resistance is (Pin 7): Programmable Charge TerminationTimer and Shutdown Input. Pulling this pin below theshutdown threshold voltage will shut down the chargerreducing the supply current to approximately 40 A andthe battery drain current to near 0 A.

7 A capacitor on thispin programs the charge termination (Pin 8): Open-Drain Charge Status Output. Whenthe battery is being charged, the CHRG pin is pulled low byan internal N-channel MOSFET. When the timer has timedout (terminating the charge cycle) or when the LTC4056 isin shutdown, but power is applied to the IC ( , VCC >VUVLOI), a 12 A current source is connected from theCHRG pin to ground. The CHRG pin is forced to a highimpedance state when input power is not present ( , VCC< VUVLOD).VCC (Pin 1): Positive Input Supply Voltage. This pinsupplies power to the internal control circuitry and exter-nal PNP transistor through the internal current senseresistor. This pin should be bypassed to ground with acapacitor in the range of 1 F to 10 (Pin 2): Sense Node for Charge Current. Currentfrom VCC passes through the internal current sense resis-tor and out of the ISENSE pin to supply current to the emitterof the external PNP transistor.

8 The collector of the PNPprovides charge current to the (Pin 3): Base Drive Output for the External PNPPass Transistor. Provides a controlled sink current todrive the base of the PNP. This pin has current (Pin 4): Ground. Provides a reference for the internalvoltage regulator and a return for all internal in the constant voltage mode, the LTC4056 willprecisely regulate the voltage between the BAT and GNDpins. The battery ground should connect close to the GNDpin to avoid voltage drop (Pin 5): Charge Current Programming Pin. Pro-vides a virtual reference voltage of 1V for an externalresistor (RPROG) connected between this pin and groundto program the battery charge current. In constant currentmode the typical charge current is 915 times the currentthrough this resistor (ICHG = 915V/RPROG). Current islimited to approximately (ICHG of ).PI FU CTIO + + VCC100 12 VOLTAGEREFERENCEOUTPUTDRIVERTEMPERATUREA NDCURRENT LIMITDRIVEBAT +VA+ C1 ITRIKL20 IPROGIPROG7 A+20 APROGGND54632187 BLOCK DIAGRA the battery accepts charge, its voltage rises.

9 When itreaches the preset float voltage of , a precisely divideddown version of this voltage ( ) is compared to internal reference voltage by amplifier VA. If thebattery voltage attempts to exceed ( at the inputof amplifier VA), the amplifier will divert current away fromthe output driver thus limiting charge current to on the battery. This is the constant voltage external capacitor on the TIMER/SHDN pin and theresistance between the PROG pin and ground set the totalcharge time. When this time elapses, the charge cycleterminates and the CHRG pin transitions from a strongpull-down to a weak 12 A pull-down. To restart the chargecycle, simply remove the input voltage and reapply it ormomentarily force the TIMER/SHDN pin to ground. Thecharge cycle will also restart if the BAT pin voltage fallsbelow the recharge threshold (VRECHRG is nominally ).When VCC is applied, pulling the TIMER/SHDN pin toground will manually shut down the charger and reset thetimer.

10 When this pin is released an internal 7 A currentsource pulls the TIMER/SHDN pin above the shut-down threshold to resume conditions such as overheating of the die or exces-sive DRIVE pin or PROG pin current are monitored input power is removed or manual shutdown isentered, the charger will drain only tiny leakage currents(<1 A) from the battery, thus maximizing battery standbytime. With VCC removed the external PNP base is con-nected to the battery by the charger. In manual shutdownthe base is connected to VCC by the LTC4056 is a linear battery charger controller with aprogrammable charge termination timer. Operation canbe understood by referring to the Block Diagram. A chargecycle begins when VCC rises above the UVLO (undervoltagelockout) threshold VUVLOI (nominally ), an externalcurrent programming resistor is connected between thePROG pin and ground and the TIMER/SHDN pin is allowedto rise above the shutdown threshold VMSDT ( ).