LTC4057-4.2 Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Programmable Charge Current up to 800mA No External MOSFET, Sense Resistor or Blocking Diode Required Constant-Current/Constant-Voltage Operation with Thermal Regulation Maximizes Charge Rate Without Risk of Overheating* Charges Single Cell Li-Ion Batteries Directly from USB Port Preset 4.2V Charge Voltage with ±1% Accuracy Current Monitor Pin for Charge Termination 25µA Supply Current in Shutdown Mode Low Battery Charge Conditioning (Trickle Charging) Soft-Start Limits Inrush Current Available in a Low Profile (1mm) SOT-23 Package U APPLICATIO S ■ ■ ■ The LTC®4057 is a constant-current/constant-voltage linear charger for single-cell lithium-ion batteries. Its ThinSOTTM package and low external component count make the LTC4057 especially well suited for portable applications. Furthermore, the LTC4057 is specifically designed to work within USB power specifications. No external sense resistor is needed and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback prevents overheating by regulating the charge current to limit the die temperature during high power operation or high ambient temperature conditions. The charge voltage is preset at 4.2V and the charge current can be programmed externally with a single resistor. When the input supply (wall adapter or USB supply) is removed, the LTC4057 automatically enters a low current state, dropping the battery drain current to less than 2µA. With power applied, the LTC4057 can be put into shutdown mode, reducing the supply current to 25µA. Wireless PDAs Cellular Phones Portable Electronics , LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. *U.S. Patent No. 6522118 For the standalone version (on-board charge termination) of the LTC4057, refer to the LTC4054. U TYPICAL APPLICATIO Charge Curve (750mAh Battery) 700 VIN 5V 600 BAT LTC4057-4.2 ON OFF 1µF 1 SHDN PROG GND 2 + 5 1.65k 4057 TA01a 1-CELL 4.2V Li-Ion BATTERY CONSTANT POWER 500 4.5 CONSTANT VOLTAGE 4.25 400 4.0 300 3.75 3.5 200 VCC = 5V θJA = 130°C/W RPROG = 1.65kΩ TA = 25°C 100 0 0 BATTERY VOLTAGE (V) VCC 3 CHARGE CURRENT (mA) 600mA 4 4.75 CONSTANT CURRENT 3.25 3.0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 TIME (HOURS) 4057 TA01b 4057f 1 LTC4057-4.2 U W W W ABSOLUTE AXI U RATI GS (Note 1) Input Supply Voltage (VCC) ........................– 0.3V to 10V PROG .............................................. – 0.3V to VCC + 0.3V BAT ..............................................................– 0.3V to 7V SHDN .........................................................– 0.3V to 10V BAT Short Circuit Duration ........................... Continuous BAT Pin Current .................................................. 800mA PROG Pin Current ................................................ 800µA Junction Temperature ........................................... 125°C Operating Ambient Temperature Range (Note 2) .............................................. – 40°C to 85°C Storage Temperature Range ................. – 65°C to 125°C Lead Temperature (Soldering, 10 sec).................. 300°C U W U PACKAGE/ORDER I FOR ATIO ORDER PART NUMBER TOP VIEW SHDN 1 LTC4057ES5-4.2 5 PROG GND 2 BAT 3 S5 PART MARKING 4 VCC S5 PACKAGE 5-LEAD PLASTIC SOT-23 LTAEW TJMAX = 125°C, (θJA = 100°C/W TO 150°C/W DEPENDING ON PC BOARD LAYOUT) (NOTE 3) Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V SYMBOL PARAMETER CONDITIONS MIN VCC Input Supply Voltage ICC Input Supply Current VFLOAT Regulated Output (Float) Voltage IBAT = 40mA, 0°C < TA < 85°C IBAT BAT Pin Charge Current RPROG = 10k; Current Mode RPROG = 2k; Current Mode Shutdown Mode (SHDN = 0V) Sleep Mode (VCC = 0V) ● ● ITRIKL Trickle Charge Current VBAT < 2.9V; RPROG = 2k (ICHG = 500mA) ● VTRIKL Trickle Charge Threshold Voltage RPROG = 10k; VBAT Rising Hysteresis VUV VCC Undervoltage Lockout Voltage From Low to High Hysteresis VASD VCC - VBAT Lockout Threshold Voltage VCC from Low to High VCC from High to Low VPROG PROG Pin Voltage RPROG = 10k; Current Mode VSHDN-IL SHDN Pin Input Low Voltage VSHDN-IH SHDN Pin Input High Voltage ISHDN SHDN Pin Input Current TLIM Junction Temperature in Constant-Temperature Mode 120 °C RON Power FET “ON” Resistance (Between VCC and BAT) 600 mΩ tSS Soft-Start Time 100 µs ● IBAT = 0mA, RPROG = 2k Shutdown Mode (SHDN = 0V, VCC < VBAT, or VCC < VUV) VSHDN = 5V IBAT = 0 to IBAT = 1000V/RPROG 4.25 ● ● MAX UNITS 6.5 V 200 600 50 µA µA 4.158 4.2 4.242 93 465 100 500 ±1 ±1 107 535 ±2 ±2 mA mA µA µA 20 50 70 mA 2.8 60 2.9 80 3.0 110 V mV 3.7 150 3.8 200 3.9 300 V mV 70 5 100 30 150 70 mV mV 0.93 1.0 1.07 V 0.4 0.65 ● ● ● ● TYP V V 0.65 1.0 V 5 15 µA 4057f 2 LTC4057-4.2 ELECTRICAL CHARACTERISTICS Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC4057 is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: See Thermal Considerations. U W TYPICAL PERFOR A CE CHARACTERISTICS PROG Pin Voltage vs Supply Voltage (Constant Current Mode) 1.015 1.0100 VCC = 5V VBAT = 4V TA = 25°C RPROG = 10k 1.0075 VCC = 5V TA = 25°C 500 RPROG = 2k 1.0050 VPROG (V) 1.005 VPROG (V) 600 VCC = 5V VBAT = 4V RPROG = 10k 1.000 400 1.0025 IBAT (mA) 1.010 Charge Current vs PROG Pin Voltage PROG Pin Voltage vs Temperature (Constant Current Mode) 1.0000 0.9975 0.995 300 200 0.9950 0.990 0.985 100 0.9925 4.0 4.5 5.0 5.5 VCC (V) 6.0 6.5 0.9900 –50 7.0 –25 0 25 50 TEMPERATURE (°C) 75 4057 G01 4.215 1.25 1.00 Regulated Output (Float) Voltage vs Supply Voltage 4.220 VCC = 5V TA = 25°C RPROG = 1.25k 4.22 0.50 0.75 VPROG (V) 4057 G03 Regulated Output (Float) Voltage vs Temperature 4.26 4.24 0.25 0 4057 G02 Regulated Output (Float) Voltage vs Charge Current 4.215 VCC = 5V RPROG = 10k 4.210 TA = 25°C RPROG = 10k 4.210 4.18 4.16 4.200 4.195 4.14 4.190 4.12 4.185 4.10 0 100 200 300 400 IBAT (mA) 500 600 700 4.205 4.205 VFLOAT (V) 4.20 VFLOAT (V) VFLOAT (V) 0 100 4.180 –50 4.195 4.190 –25 0 25 50 75 100 TEMPERATURE (°C) 4057 G04 4.200 4057 G05 4.185 4.0 4.5 5.0 5.5 VCC (V) 6.0 6.5 7.0 4057 G06 4057f 3 LTC4057-4.2 U W TYPICAL PERFOR A CE CHARACTERISTICS SHDN Threshold Voltage vs Temperature and Supply Voltage Trickle Charge Current vs Supply Voltage Trickle Charge Current vs Temperature 1.0 60 60 RPROG = 2k ITRIKL (mA) VSHDN (V) 0.8 VCC = 6.5V 0.7 VCC = 4.2V 0.6 RPROG = 2k 50 50 40 40 ITRIKL (mA) 0.9 VCC = 5V VBAT = 2.5V 30 20 0.5 20 RPROG = 10k 10 0.4 –50 –25 0 25 50 TEMPERATURE (°C) 75 0 –50 100 0 25 50 TEMPERATURE (°C) –25 75 2.975 0 100 4.0 VCC = 5V RPROG = 10k 4.5 5.0 5.5 VCC (V) 6.0 6.5 7.0 4057 G08 4057 G09 Charge Current vs Battery Voltage Charge Current vs Supply Voltage 600 600 3.000 RPROG = 10k 10 4057 G07 Trickle Charge Threshold vs Temperature VBAT = 2.5V TA = 25°C 30 RPROG = 2k TA = 0°C 500 500 TA = 40°C 2.900 2.875 400 IBAT (mA) 400 2.925 IBAT (mA) VTRIKL (V) 2.950 TA = 25°C 300 VBAT = 4V TA = 25°C θJA = 125°C/W 300 200 200 2.850 2.825 2.800 –50 VCC = 5V θJA = 125°C/W RPROG = 2k 100 –25 0 25 50 TEMPERATURE (°C) 75 0 2.7 100 3.0 3.3 3.6 3.9 VBAT (V) 4.5 4.0 5.0 4.5 5.5 VCC (V) 6.0 6.5 7.0 4057 G12 4057 G11 Charge Current vs Ambient Temperature Power FET “ON” Resistance vs Temperature 600 700 RPROG = 2k 500 650 400 600 VCC = 5V VBAT = 4V θJA = 80°C/W RDS(ON) (mΩ) IBAT (mA) 0 4.2 4057 G10 300 RPROG = 10k 100 ONSET OF THERMAL REGULATION 200 VCC = 4.2V VBAT = 4V RPROG = 2k 550 500 RPROG = 10k 100 0 –50 –25 450 50 100 25 75 0 AMBIENT TEMPERATURE (°C) 125 4057 G13 400 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 125 4057 G14 4057f 4 LTC4057-4.2 W U U U PI FU CTIO S BLOCK DIAGRA SHDN (Pin 1): Shutdown Input. Pulling this pin low puts the LTC4057 in shutdown mode, thus stopping the charge current. In shutdown mode, the input supply current drops to 25µA and the battery drain current drops to less than 2µA. This pin has an internal 1MΩ resistor to GND. VCC 4 120°C TA TDIE 1× 1000× GND (Pin 2): Ground. BAT (Pin 3): Charge Current Output. Provides charge current to the battery and regulates the final float voltage to 4.2V. An internal precision resistor divider from this pin sets the float voltage and is disconnected in shutdown mode. IBAT = (VPROG/RPROG) • 1000 3 BAT 5µA MA R1 + VA R2 – CA VCC (Pin 4): Positive Input Supply Voltage. Provides power to the charger. VCC can range from 4.25V to 6.5V and should be bypassed with at least a 1µF capacitor. When VCC drops to within 30mV of the BAT pin voltage, the LTC4057 enters shutdown mode, dropping IBAT to less than 2µA. PROG (Pin 5): Charge Current Program and Charge Current Monitor Pin. The charge current is programmed by connecting a 1% resistor, RPROG, to ground. 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: + – – + REF 1.21V R3 1V R4 0.1V R5 SHDN 1 +1 1MΩ C1 – + 2.9V TO BAT 5 RPROG 2 PROG GND 4-57 BD This pin is clamped to approximately 2.4V. Driving this pin to voltages beyond the clamp voltage will draw currents as high as 1.5mA. 4057f 5 LTC4057-4.2 U OPERATIO The LTC4057 is a single-cell lithium-ion battery charger using a constant-current/constant-voltage algorithm. It can deliver up to 800mA of charge current (using a good thermal PC board layout) with a final float voltage accuracy of ±1%. The LTC4057 includes an internal P-channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is required and the LTC4057 is capable of operating from a USB power source. Normal Charge Charging begins when SHDN is high, the voltage at the VCC pin rises above the UVLO threshold level and a program resistor is connected from the PROG pin to ground. If the BAT pin voltage is below 2.9V, the charger enters tricklecharge mode. In this mode, the LTC4057 supplies approximately 1/10 the programmed charge current to bring the battery voltage up to a safe level for full current charging. When the BAT pin voltage rises above 2.9V, the charger enters constant-current mode, where the programmed charge current is supplied to the battery. When the BAT pin approaches the final float voltage (4.2V), the LTC4057 enters constant-voltage mode, and the charge current begins to decrease. Programming Charge Current The charge current is programmed using a single resistor from the PROG pin to ground. The charge current is 1000 times the current out of the PROG pin. The program resistor and the charge current are calculated using the following equations: RPROG = 1000V 1000V , ICHG = ICHG RPROG 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: IBAT = VPROG •1000 RPROG Thermal Limiting An internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 120°C. This feature protects the LTC4057 from excessive temperature and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the LTC4057. The charge current can be set according to typical (not worst-case) ambient temperature with the assurance that the charger will automatically reduce the current in worst-case conditions. ThinSOT power considerations are discussed further in the Applications Information section. Undervoltage Lockout (UVLO) An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until VCC rises above the undervoltage lockout threshold. The UVLO circuit has a built-in hysteresis of 200mV. Furthermore, to protect against reverse current in the power MOSFET, the UVLO circuit keeps the charger in shutdown mode if VCC falls to within 30mV of the battery voltage. If the UVLO comparator is tripped, the charger will not come out of shutdown mode until VCC rises 100mV above the battery voltage. Shutdown Mode The LTC4057 can also be put into shutdown mode at any time by applying logic “low” to the SHDN pin (VSHDN < 0.4V). This reduces the battery drain current to less than 2µA and the input supply current to less than 50µA. Charging will resume when applying a logic “high” to the SHDN pin (VSHDN > 1V). 4057f 6 LTC4057-4.2 U W U U APPLICATIO S I FOR ATIO Stability Considerations The constant-voltage mode feedback loop is stable without an output capacitor provided a battery is connected to the charge output. When an output capacitor is used, especially high value low ESR ceramic types, it is recommended that a 1Ω resistor be placed in series with the capacitor to stabilize the voltage loop. The loop stability is determined by the bypass capacitor as well as the effective series resistance of the battery. When the battery is disconnected and the LTC4057 is still powered, the voltage regulation loop should be compensated by placing a capacitor greater than 1µF from the BAT pin to ground with a 1Ω to 2Ω resistor in series with this capacitor. Alternatively, powering down the LTC4057 or placing it into shutdown mode when the battery is disconnected avoids this problem. In constant-current mode, the PROG pin is in the feedback loop, not the battery. The constant-current mode stability is affected by the impedance at the PROG pin. With no additional capacitance on the PROG pin, the charger is stable with program resistor values as high as 20k. However, additional capacitance on this node reduces the maximum allowed program resistor value. The pole frequency at the PROG pin should be kept above 100kHz. Therefore, if the PROG pin is loaded with a capacitance, CPROG, the following equation can be used to calculate the maximum resistance value for RPROG: RPROG ≤ 1 2π • 105 • C PROG Average, rather than instantaneous, battery current may be of interest to the user. For example, if a switching power supply 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 filter can be used on the PROG pin to measure the average battery current as shown in Figure 1. A 10k resistor has been added between the PROG pin and the filter capacitor to ensure stability. LTC4057-4.2 10k CHARGE CURRENT MONITOR CIRCUITRY PROG GND CFILTER RPROG 4057 F01 Figure 1. Isolating Capacitive Load on PROG Pin and Filtering Power Dissipation The conditions that cause the LTC4057 to reduce charge current through thermal feedback can be approximated by considering the power dissipated in the IC. Nearly all of this power dissipation is generated by the internal MOSFET. This is calculated to be approximately: PD = (VCC – VBAT) • IBAT where PD is the power dissipated, VCC is the input supply voltage, VBAT is the battery voltage, and IBAT is the charge current. The approximate ambient temperature at which the thermal feedback begins to protect the IC is: TA = 120°C – PDθJA TA = 120°C – (VCC – VBAT) • IBAT • θJA Example: An LTC4057 operating from a 4.5V USB supply is programmed to supply 600mA full-scale current to a discharged Li-Ion battery with a voltage of 3.7V. Assuming θJA is 150°C/W (see Board Layout Considerations), the ambient temperature at which the LTC4057 will begin to reduce the charge current is approximately: TA = 120°C – (4.5V – 3.7V) • (600mA) • 150°C/W TA = 120°C – 0.48W • 150°C/W = 120°C – 72°C TA = 48°C The LTC4057 can be used above 48°C ambient, but the charge current will be reduced from 600mA. The approximate current at a given ambient temperature can be approximated by: IBAT = 120°C – TA (VCC − VBAT )• θ JA 4057f 7 LTC4057-4.2 U W U U APPLICATIO S I FOR ATIO Using the previous example with an ambient temperature of 60°C, the charge current will be reduced to approximately: 120°C – 60°C 60°C = (4.5V – 3.7V)• 150°C / W 120°C / A = 500mA IBAT = IBAT Moreover, when thermal feedback reduces the charge current, the voltage at the PROG pin is also reduced proportionally as discussed in the Operation section. It is important to remember that LTC4057 applications do not need to be designed for worst-case thermal conditions since the IC will automatically reduce power dissipation when the junction temperature reaches approximately 120°C. Thermal Considerations Because of the small size of the ThinSOT package, it is very important to use a good thermal PC board layout to maximize the available charge current. The thermal path for the heat generated by the IC is from the die to the copper lead frame, through the package leads, (especially the ground lead) to the PC board copper. The PC board copper is the heat sink. The footprint copper pads should be as wide as possible and expand out to larger copper areas to spread and dissipate the heat to the surrounding ambient. Feedthrough vias to inner or backside copper layers are also useful in improving the overall thermal performance of the charger. Other heat sources on the board, not related to the charger, must also be considered when designing a PC board layout because they will affect overall temperature rise and the maximum charge current. Table 1 lists thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 board with one ounce copper. Table 1. Measured Thermal Resistance THERMAL RESISTANCE COPPER AREA TOPSIDE* BACKSIDE BOARD AREA JUNCTION-TOAMBIENT 2500mm2 2500mm2 2500mm2 125°C/W 1000mm2 2500mm2 2500mm2 125°C/W 225mm2 2500mm2 2500mm2 130°C/W 100mm2 2500mm2 2500mm2 135°C/W 50mm2 2500mm2 2500mm2 150°C/W *Device is mounted on topside. Increasing Thermal Regulation Current Reducing the voltage drop across the internal MOSFET can significantly decrease the power dissipation in the IC. This has the effect of increasing the current delivered to the battery during thermal regulation. One method is by dissipating some of the power through an external component, such as a resistor or diode. Example: An LTC4057-4.2 operating from a 5V wall adapter is programmed to supply 800mA full-scale current to a discharged Li-Ion battery with a voltage of 3.75V. Assuming θJA is 125°C/W, the approximate charge current at an ambient temperature of 25°C is: IBAT = 120°C – 25°C = 608mA (5V – 3.75V)• 125°C / W By dropping voltage across a resistor in series with a 5V wall adapter (shown in Figure 2), the on-chip power dissipation can be decreased, thus increasing the thermally regulated charge current. IBAT = 120°C – 25°C (VS – IBATRCC – VBAT )• θ JA 4057f 8 LTC4057-4.2 U W U U APPLICATIO S I FOR ATIO While this application delivers more energy to the battery and reduces charge time in thermal mode, it may actually lengthen charge time in voltage mode if VCC becomes low enough to put the LTC4057 into dropout. Figure 3 shows how this circuit can result in dropout as RCC becomes large. VS RCC 4 VCC BAT 1µF 3 LTC4057-4.2 PROG GND 2 5 + Li-Ion CELL RPROG 405742 F02 Figure 2. A Circuit to Maximize Thermal Mode Charge Current This technique works best when RCC values are minimized to keep component size small and avoid dropout. Remember to choose a resistor with adequate power handling capability. 1000 VS = 5V Solving for IBAT using the quadratic formula1. 4R (120°C – TA ) (VS – VBAT ) – (VS – VBAT )2 CC θ JA 2RCC Using RCC = 0.25Ω, VS = 5V, VBAT = 3.75V, TA = 25°C and θJA = 125°C/W, we can calculate the thermally regulated charge current to be: IBAT = 708.4mA 800 CHARGE CURRENT (mA) IBAT = CONSTANT CURRENT 600 VS = 5.5V 400 THERMAL MODE VS = 5.25V DROPOUT VBAT = 3.75V TA = 25°C θJA = 125°C/W RPROG = 1.25kΩ 200 0 0 0.25 0.5 0.75 1.0 RCC (Ω) 1.25 1.5 1.75 405442 F03 Figure 3. Charge Current vs RCC Note 1: Large values of RCC will result in no solution for IBAT. This indicates that the LTC4057 will not generate enough heat to require thermal regulation. 4057f 9 LTC4057-4.2 U W U U APPLICATIO S I FOR ATIO VCC Bypass Capacitor Charge Current Soft-Start Many types of capacitors can be used for input bypassing; however, caution must be exercised when using multilayer 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 conditions, such as connecting the charger input to a live power source. Adding a 1.5Ω resistor in series with an X5R ceramic capacitor will minimize start-up voltage transients. For more information, refer to Application Note 88. The LTC4057 includes a soft-start circuit to minimize the inrush current at the start of a charge cycle. When charging begins, the charge current ramps from zero to the fullscale current over a period of approximately 100µs. This has the effect of minimizing the transient current load on the power supply during startup. 4057f 10 LTC4057-4.2 U PACKAGE DESCRIPTIO S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 1.90 BSC S5 TSOT-23 0302 4057f 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. 11 LTC4057-4.2 U TYPICAL APPLICATIO S 800mA Li-Ion Charger with External Power Dissipation Basic Li-Ion Battery Charger with Reverse Polarity Input Protection VIN = 5V 0.25Ω 4 1µF 800mA VCC BAT 4 5V WALL ADAPTER 3 SHDN ON OFF GND 2 PROG 3 BAT 500mA LTC4057-4.2 LTC4057-4.2 2 VCC 5 1µF + ON OFF 2 SHDN 1.25k GND 2 + 5 PROG 2k 4057 TA03 4057 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1571 200kHz/500kHz Switching Battery Charger Up to 1.5A Charge Current; Preset and Adjustable Battery Voltages LTC1729 Lithium-Ion Battery Charger Termination Controllers Time or Charge Current Termination, Preconditioning 8-Lead MSOP LTC1730 Lithium-Ion Battery Pulse Charger No Blocking Diode Required, Current Limit for Maximum Safety LTC1731 Lithium-Ion Linear Battery Charger Controller Simple Charger uses External FET, Features Preset Voltages, C/10 Charger Detection and Programmable Timer LTC1732 Lithium-Ion Linear Battery Charger Controller Simple Charger uses External FET, Features Preset Voltages, C/10 Charger Detection and Programmable Timer, Input Power Good Indication LTC1733 Monolithic Lithium-Ion Linear Battery Charger Standalone Charger with Programmable Timer, Up to 1.5A Charge Current LTC1734 Lithium-Ion Linear Battery Charger in ThinSOT Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed LTC1734L Lithium-Ion Linear Battery Charger in ThinSOT Low Charge Current Version of LTC1734 LTC1998 Lithium-Ion Low Battery Detector 1% Accurate 2.5µA Quiescent Current, SOT-23 LTC4050 Lithium-Ion Linear Battery Charger Controller Simple Charger uses External FET, Features Preset Voltages, C/10 Charger Detection and Programmable Timer, Input Power Good Indication, Thermistor Interface LTC4052 Monolithic Lithium-Ion Battery Pulse Charger No Blocking Diode or External Power FET Required LTC4053 USB Compatible Monolithic Li-Ion Battery Charger Standalone Charger with Programmable Timer, Up to 1.25A Charge Current LTC4054 Standalone Linear Li-Ion Battery Charger with Integrated Pass Transistor in ThinSOT Thermal Regulation Prevents Overheating, C/10 Termination, C/10 Indicator LTC4410 USB Power Manager For Simultaneous Operation of USB Peripheral and Battery Charging from USB Port, Keeps Current Drawn from USB Port Constant, Keeps Battery Fresh, Use with the LTC4053, LTC1733, or LTC4054 4057f 12 Linear Technology Corporation LT/TP 0503 1K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2003