LTC4052-4.2 Lithium-Ion Battery Pulse Charger with Overcurrent Protection FEATURES DESCRIPTIO n Very Low Power Dissipation: 350mW at 1A The LTC 4052 is a complete standalone pulse charger n Complete Standalone Pulse Charger for 1-Cell with integrated MOSFET for 1-cell lithium-ion batteries. Lithium-Ion Batteries An external sense resistor provides overcurrent limiting as n Requires No Microcontroller, MOSFET or a safety precaution against a user connecting a wall Blocking Diode adapter with the incorrect or no current limit. The internal n Sense Resistor Limits Maximum Current for Safety MOSFET prevents reverse battery current from flowing if n Programmable Charge Termination Timer for the input voltage is shorted to ground, eliminating the Maximum Capacity Charging need for a blocking diode. n 1% Float Voltage Accuracy n As the battery accepts charge and approaches the Near End-of-Charge (C/10) Detection Output n programmed float voltage, the internal MOSFET begins AC Wall Adapter Present Output n switching off and on with the duty cycle gradually decreas- Low Battery Drain when Input Supply Is Removed n ing as the battery approaches a fully charged condition. Automatic Trickle Charge for Low Battery n A programmable timer terminates the charge cycle. The Automatic Battery Refresh n near end-of-charge C/10 condition is indicated at the Thermal Shutdown Protection n CHRG pin when the average charge current falls to one- Tiny Thermally Enhanced MSOP Package tenth of the wall adapter current. Removing the input U APPLICATIO S voltage puts the LTC4052 into a sleep mode, dropping the battery current drain to less than 1m A. n Handheld Computers The LTC4052 is available in a tiny 8-pin thermally n Cellular Telephones enhanced MSOP package. n Cradle Chargers , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO Single Cell 4.2V, 1A, Standalone Li-Ion Battery Charger LTC4052 Charge Profile V = 4.5V TO 10V 4.5 IN WITH 1A CURRENT LIMIT 3 4.0 4.7 10k CHARGE V IN 1k R 3.5 CYCLE SENSE 1F 0.05 ENDS 0.047F 1k CONSTANT PULSING LTC4052 3.0 CURRENT CURRENT 7 GATE CHARGE STATUS 1.0 6 0.022F CHRG AC PRESENT 0.5 2 1 ACPR SENSE 0 C/10 8 BAT 5 1-CELL 4.2V TIMER GND Li-Ion 0 BATTERY 5 4 0 0.5 1.0 1.5 2.0 2.5 3.0 C TIMER TIME (HOURS) 0.1F 4052 TA01 4052 TA01b 405242f 1 CHARGE BATTERY CHRG (V) CURRENT (A) VOLTAGE (V) U ULTC4052-4.2 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) ORDER PART Input Supply Voltage (V )....................................... 12V IN NUMBER TOP VIEW BAT Voltage ...............................................0.3V to 12V SENSE 1 8 BAT GATE (Note 2) .............................................0.3V to 8V ACPR 2 7 GATE LTC4052EMS8E-4.2 V 3 6 CHRG SENSE, TIMER.................................. 0.3V to V +0.3V IN IN GND 4 5 TIMER CHRG, ACPR .............................................0.3V to 12V MSE EXPOSED PAD PACKAGE SENSE, BAT Peak Current ...................................... 1.5A 8-LEAD PLASTIC MSOP MS8 PART MARKING T = 125 C, q = 35 C/W JMAX JA Operating Temperature Range (Note 3) .. 40 C to 85 C EXPOSED PAD IS GROUND. LTYY Junction Temperature (Note 4)............................. 125 C (MUST BE SOLDERED TO PCB). Storage Temperature Range ................. 65 C to 150 C Lead Temperature (Soldering, 10 sec).................. 300 C Consult LTC Marketing for parts specified with wider operating temperature ranges. DC ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 6V unless otherwise noted. A IN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Supply Voltage Wall Adapter Open Circuit Voltage l 4.5 10 V IN I Input Quiescent Supply Current Full Charge Mode l 0.7 1.4 mA IN V Battery Float Voltage 0 C T 85 C 4.158 4.200 4.242 V BAT A l 4.137 4.200 4.242 V V Recharge Battery Voltage Threshold Battery Voltage Falling 0 C T 85 C 3.990 4.050 4.110 V RECHRG A l 3.969 4.050 4.110 V V V V Margin l 75 150 225 mV MARGIN BAT RECHRG V Overcurrent Trip Sense Voltage l 90 105 120 mV IMAX I Trickle Charge Current V = 2V l 14 24 34 mA TRICKLE BAT V Trickle Charge Threshold Voltage V Rising l 2.35 2.45 2.55 V TRICKLE BAT R Internal Switch On-Resistance V = 2.6V 0.45 0.7 W DS(ON) BAT V = 4V 0.35 0.5 W BAT V GATE Pin Voltage V = 2.6V 6.5 V GATE BAT V = 4V 10.5 V BAT T TIMER Period Accuracy C = 0.1m F, Full Charge Mode 10 % TIMER TIMER I Battery Leakage Current Through Charger V = 4V, V = 0V l 1 m A LEAK BAT IN V Sleep Threshold Voltage (V V ) Low to High 20 45 70 mV SLEEP IN BAT (V V ) High to Low 0 15 mV IN BAT V ACPR Pin Output Low Voltage I = 3mA l 0.5 0.8 V ACPR ACPR I ACPR Pin Leakage Current V = 0, V = 6V l 1 m A LEAKACPR IN ACPR V CHRG Pin Output Low Voltage I = 3mA, Charging, C/10 Not Reached l 0.5 0.8 V CHRG CHRG I CHRG Pin Leakage Current V = 0, V = 6V l 1 m A LEAKCHRG IN CHRG I CHRG Pin Weak Pull-Down Current V = 1V, Charging, C/10 Reached 20 40 70 m A CHRG CHRG 405242f 2 U WWW