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LTC4057-4.2 Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT
FEATURES
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DESCRIPTIO
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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 25A 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
The LTC(R)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 2A. With power applied, the LTC4057 can be put into shutdown mode, reducing the supply current to 25A. For the standalone version (on-board charge termination) of the LTC4057, refer to the LTC4054.
APPLICATIO S
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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
TYPICAL APPLICATIO
VIN 5V 4 VCC BAT 3
Charge Curve (750mAh Battery)
700
600mA
600
CONSTANT CURRENT CONSTANT POWER CONSTANT VOLTAGE
CHARGE CURRENT (mA)
500 400 300 200 100 0 0
LTC4057-4.2 ON OFF 1F 1 SHDN PROG GND 2 5
+
1.65k
1-CELL 4.2V Li-Ion BATTERY
4057 TA01a
VCC = 5V JA = 130C/W RPROG = 1.65k TA = 25C
3.0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 TIME (HOURS)
4057 TA01b
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4.75 4.5
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BATTERY VOLTAGE (V)
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4.25 4.0 3.75 3.5 3.25
1
LTC4057-4.2
ABSOLUTE
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
ORDER PART NUMBER
TOP VIEW SHDN 1 GND 2 BAT 3 4 VCC 5 PROG
(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 ................................................ 800A Junction Temperature ........................................... 125C Operating Ambient Temperature Range (Note 2) .............................................. - 40C to 85C Storage Temperature Range ................. - 65C to 125C Lead Temperature (Soldering, 10 sec).................. 300C
LTC4057ES5-4.2 S5 PART MARKING LTAEW
S5 PACKAGE 5-LEAD PLASTIC SOT-23
TJMAX = 125C, (JA = 100C/W TO 150C/W DEPENDING ON PC BOARD LAYOUT) (NOTE 3)
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 5V
SYMBOL VCC ICC PARAMETER Input Supply Voltage Input Supply Current IBAT = 0mA, RPROG = 2k Shutdown Mode (SHDN = 0V, VCC < VBAT, or VCC < VUV) IBAT = 40mA, 0C < TA < 85C RPROG = 10k; Current Mode RPROG = 2k; Current Mode Shutdown Mode (SHDN = 0V) Sleep Mode (VCC = 0V) VBAT < 2.9V; RPROG = 2k (ICHG = 500mA) RPROG = 10k; VBAT Rising Hysteresis From Low to High Hysteresis VCC from Low to High VCC from High to Low RPROG = 10k; Current Mode
q q q q q
ELECTRICAL CHARACTERISTICS
CONDITIONS
q q q
MIN 4.25
TYP 200
MAX 6.5 600 50 4.242 107 535 2 2 70 3.0 110 3.9 300 150 70 1.07 1.0 15
UNITS V A A V mA mA A A mA V mV V mV mV mV V V V A C m s
VFLOAT IBAT
Regulated Output (Float) Voltage BAT Pin Charge Current
4.158 93 465
4.2 100 500 1 1 50 2.9 80 3.8 200 100 30 1.0 0.65 0.65 5 120 600
ITRIKL VTRIKL VUV VASD VPROG VSHDN-IL VSHDN-IH ISHDN TLIM RON tSS
Trickle Charge Current Trickle Charge Threshold Voltage VCC Undervoltage Lockout Voltage VCC - VBAT Lockout Threshold Voltage PROG Pin Voltage SHDN Pin Input Low Voltage SHDN Pin Input High Voltage SHDN Pin Input Current Junction Temperature in Constant-Temperature Mode Power FET "ON" Resistance (Between VCC and BAT) Soft-Start Time
q
20 2.8 60 3.7 150 70 5 0.93 0.4
VSHDN = 5V
q
IBAT = 0 to IBAT = 1000V/RPROG
100
2
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WW
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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 0C to 70C. Specifications over the -40C to 85C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: See Thermal Considerations.
TYPICAL PERFOR A CE CHARACTERISTICS
PROG Pin Voltage vs Supply Voltage (Constant Current Mode)
1.015 1.010 1.005 VPROG (V) VPROG (V) 1.000 0.995 0.990 0.985 VCC = 5V VBAT = 4V TA = 25C RPROG = 10k 1.0100 1.0075 1.0050 IBAT (mA) 75 1.0025 1.0000 0.9975 0.9950 0.9925 4.0 4.5 5.0 5.5 VCC (V) 6.0 6.5 7.0
4057 G01
Regulated Output (Float) Voltage vs Charge Current
4.26 4.24 4.22 VFLOAT (V) 4.20 4.18 4.16 4.14 4.12 4.10 0 100 200 300 400 IBAT (mA) 500 600 700 VCC = 5V TA = 25C RPROG = 1.25k 4.220 4.215 4.210 VFLOAT (V)
4.200 4.195 4.190 4.185 4.180 -50 -25 0 25 50 75 100
4057 G05
VFLOAT (V)
UW
4057 G04
PROG Pin Voltage vs Temperature (Constant Current Mode)
600 VCC = 5V VBAT = 4V RPROG = 10k
Charge Current vs PROG Pin Voltage
VCC = 5V TA = 25C 500 RPROG = 2k 400 300 200 100 0
0.9900 -50
-25
0 25 50 TEMPERATURE (C)
100
4057 G02
0
0.25
0.50 0.75 VPROG (V)
1.00
1.25
4057 G03
Regulated Output (Float) Voltage vs Temperature
4.215 VCC = 5V RPROG = 10k 4.210 4.205 4.200 4.195 4.190 4.185
Regulated Output (Float) Voltage vs Supply Voltage
TA = 25C RPROG = 10k
4.205
4.0
4.5
5.0
TEMPERATURE (C)
5.5 VCC (V)
6.0
6.5
7.0
4057 G06
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LTC4057-4.2 TYPICAL PERFOR A CE CHARACTERISTICS
SHDN Threshold Voltage vs Temperature and Supply Voltage
1.0 0.9 0.8
ITRIKL (mA) VSHDN (V)
VCC = 6.5V 0.7 VCC = 4.2V 0.6 0.5 0.4 -50
30 20 10 0 -50 RPROG = 10k
VCC = 5V VBAT = 2.5V
ITRIKL (mA)
-25
0 25 50 TEMPERATURE (C)
Trickle Charge Threshold vs Temperature
3.000 2.975 2.950
VTRIKL (V) IBAT (mA)
VCC = 5V RPROG = 10k
IBAT (mA)
2.925 2.900 2.875 2.850 2.825 2.800 -50 -25 0 25 50 TEMPERATURE (C) 75 100
4057 G10
Charge Current vs Ambient Temperature
600 RPROG = 2k 500 400
IBAT (mA)
300 200
VCC = 5V VBAT = 4V JA = 80C/W
ONSET OF THERMAL REGULATION
RDS(ON) (m)
100 0 -50 -25
4
UW
75
4057 G07
Trickle Charge Current vs Temperature
60 RPROG = 2k 50 40 50 40 30 20 10 0 60
Trickle Charge Current vs Supply Voltage
RPROG = 2k
VBAT = 2.5V TA = 25C
RPROG = 10k
100
-25
0 25 50 TEMPERATURE (C)
75
100
4057 G08
4.0
4.5
5.0
5.5 VCC (V)
6.0
6.5
7.0
4057 G09
Charge Current vs Battery Voltage
600 TA = 0C 500 400 300 200 100 0 2.7 VCC = 5V JA = 125C/W RPROG = 2k 3.0 3.3 3.6 3.9 VBAT (V) 4.2 4.5
4057 G11
Charge Current vs Supply Voltage
600 RPROG = 2k 500
TA = 40C TA = 25C
400 300 200 100 0 RPROG = 10k VBAT = 4V TA = 25C JA = 125C/W
4.0
4.5
5.0
5.5 VCC (V)
6.0
6.5
7.0
4057 G12
Power FET "ON" Resistance vs Temperature
700 650 600 550 500 450 400 -50 -25 VCC = 4.2V VBAT = 4V RPROG = 2k
RPROG = 10k
50 100 25 75 0 AMBIENT TEMPERATURE (C)
125
50 25 75 0 TEMPERATURE (C)
100
125
4057 G13
4057 G14
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LTC4057-4.2
PI FU CTIO S
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 25A and the battery drain current drops to less than 2A. This pin has an internal 1M resistor to GND. 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. 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 1F capacitor. When VCC drops to within 30mV of the BAT pin voltage, the LTC4057 enters shutdown mode, dropping IBAT to less than 2A. 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: IBAT = (VPROG/RPROG) * 1000 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.
SHDN 1 1M C1 +1 CA
BLOCK DIAGRA
120C TA TDIE
-
+
REF 1.21V R3 1V R4 0.1V R5
-
2.9V
+
TO BAT 5 RPROG PROG 2 GND
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VCC 4 1x 1000x 3 BAT
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U
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-
MA
+
5A
R1
+
VA R2
-
4-57 BD
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LTC4057-4.2
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
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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 120C. 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 2A and the input supply current to less than 50A. Charging will resume when applying a logic "high" to the SHDN pin (VSHDN > 1V).
4057f
LTC4057-4.2
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 1 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 1F from the BAT pin to ground with a 1 to 2 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 2 * 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.
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LTC4057-4.2 PROG GND RPROG
4057 F01
W
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10k
CHARGE CURRENT MONITOR CIRCUITRY CFILTER
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 = 120C - PDJA TA = 120C - (VCC - VBAT) * IBAT * JA 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 JA is 150C/W (see Board Layout Considerations), the ambient temperature at which the LTC4057 will begin to reduce the charge current is approximately: TA = 120C - (4.5V - 3.7V) * (600mA) * 150C/W TA = 120C - 0.48W * 150C/W = 120C - 72C TA = 48C The LTC4057 can be used above 48C ambient, but the charge current will be reduced from 600mA. The approximate current at a given ambient temperature can be approximated by:
IBAT =
120C - TA (VCC - VBAT )* JA
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LTC4057-4.2
APPLICATIO S I FOR ATIO
Using the previous example with an ambient temperature of 60C, the charge current will be reduced to approximately:
IBAT = IBAT 120C - 60C 60C = (4.5V - 3.7V)* 150C / W 120C / A = 500mA
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 120C. 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.
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Table 1. Measured Thermal Resistance
COPPER AREA TOPSIDE* 2500mm2 1000mm2 225mm2 100mm2 50mm2 BACKSIDE 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE JUNCTION-TOAMBIENT 125C/W 125C/W 130C/W 135C/W 150C/W *Device is mounted on topside.
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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 JA is 125C/W, the approximate charge current at an ambient temperature of 25C is:
IBAT =
120C - 25C = 608mA (5V - 3.75V)* 125C / 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 =
120C - 25C (VS - IBATRCC - VBAT )* JA
4057f
LTC4057-4.2
APPLICATIO S I FOR ATIO
VS RCC 4 VCC BAT 1F LTC4057-4.2 PROG GND 2 5
3
+
RPROG
Li-Ion CELL
405742 F02
Figure 2. A Circuit to Maximize Thermal Mode Charge Current
Solving for IBAT using the quadratic formula1. IBAT = 4R (120C - TA ) (VS - VBAT ) - (VS - VBAT )2 CC JA 2RCC Using RCC = 0.25, VS = 5V, VBAT = 3.75V, TA = 25C and JA = 125C/W, we can calculate the thermally regulated charge current to be: IBAT = 708.4mA
CHARGE CURRENT (mA)
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.
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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. 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 800 CONSTANT CURRENT 600 VS = 5.5V 400 THERMAL MODE 200 VS = 5.25V DROPOUT 0 0 0.25 0.5 0.75 1.0 RCC () VBAT = 3.75V TA = 25C JA = 125C/W RPROG = 1.25k 1.25 1.5 1.75
405442 F03
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Figure 3. Charge Current vs RCC
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LTC4057-4.2
APPLICATIO S I FOR ATIO
VCC Bypass Capacitor
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 1.5 resistor in series with an X5R ceramic capacitor will minimize start-up voltage transients. For more information, refer to Application Note 88.
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Charge Current Soft-Start 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 100s. This has the effect of minimizing the transient current load on the power supply during startup.
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LTC4057-4.2
PACKAGE DESCRIPTIO
0.62 MAX
0.95 REF
3.85 MAX 2.62 REF
RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR
0.20 BSC 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
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.
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S5 Package 5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 2.80 BSC 1.50 - 1.75 (NOTE 4) PIN ONE 0.30 - 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 - 0.90 0.01 - 0.10 1.90 BSC
S5 TSOT-23 0302
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LTC4057-4.2
TYPICAL APPLICATIO S
800mA Li-Ion Charger with External Power Dissipation
VIN = 5V 0.25 4 1F 2 ON OFF VCC SHDN BAT PROG 3 5 800mA LTC4057-4.2 GND 2 5V WALL ADAPTER 1F ON OFF 4 2 3 5 500mA
1.25k
RELATED PARTS
PART NUMBER LT1571 LTC1729 LTC1730 LTC1731 LTC1732 LTC1733 LTC1734 LTC1734L LTC1998 LTC4050 DESCRIPTION 200kHz/500kHz Switching Battery Charger Lithium-Ion Battery Pulse Charger Lithium-Ion Linear Battery Charger Controller Lithium-Ion Linear Battery Charger Controller Monolithic Lithium-Ion Linear Battery Charger Lithium-Ion Linear Battery Charger in ThinSOT Lithium-Ion Linear Battery Charger in ThinSOT Lithium-Ion Low Battery Detector Lithium-Ion Linear Battery Charger Controller COMMENTS Up to 1.5A Charge Current; Preset and Adjustable Battery Voltages No Blocking Diode Required, Current Limit for Maximum Safety Simple Charger uses External FET, Features Preset Voltages, C/10 Charger Detection and Programmable Timer Simple Charger uses External FET, Features Preset Voltages, C/10 Charger Detection and Programmable Timer, Input Power Good Indication Standalone Charger with Programmable Timer, Up to 1.5A Charge Current Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed Low Charge Current Version of LTC1734 1% Accurate 2.5A Quiescent Current, SOT-23 Simple Charger uses External FET, Features Preset Voltages, C/10 Charger Detection and Programmable Timer, Input Power Good Indication, Thermistor Interface No Blocking Diode or External Power FET Required Standalone Charger with Programmable Timer, Up to 1.25A Charge Current Thermal Regulation Prevents Overheating, C/10 Termination, C/10 Indicator 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 Lithium-Ion Battery Charger Termination Controllers Time or Charge Current Termination, Preconditioning 8-Lead MSOP
LTC4052 LTC4053 LTC4054 LTC4410
Monolithic Lithium-Ion Battery Pulse Charger USB Compatible Monolithic Li-Ion Battery Charger Standalone Linear Li-Ion Battery Charger with Integrated Pass Transistor in ThinSOT USB Power Manager
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
q
FAX: (408) 434-0507 q www.linear.com
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Basic Li-Ion Battery Charger with Reverse Polarity Input Protection
VCC SHDN
BAT PROG
LTC4057-4.2
+
+
GND 2
2k
4057 TA02
4057 TA03
4057f LT/TP 0503 1K * PRINTED IN USA
(c) LINEAR TECHNOLOGY CORPORATION 2003

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