LTC1730-4/LTC1730-4.2 Lithium-Ion Battery Pulse Charger with Overcurrent Protection FEATURES DESCRIPTIO The LTC 1730 is a complete pulse charger for 1-cell n Complete Pulse Charger for 1-Cell Lithium-Ion lithium-ion batteries. When charging a depleted cell, the Batteries internal MOSFET is fully on allowing the current limited n Sense Resistor Limits Maximum Current for Safety input power source to provide charge current to the n 1% Float Voltage Accuracy battery, virtually eliminating heat generation in the charger. n End-of-Charge (C/10) Detection Output n Programmable Charge Termination Timer As the battery accepts charge and approaches the pro- n Internal 0.35W NMOS Switch grammed voltage, the internal MOSFET begins switching n No Blocking Diode Required off and on with the duty cycle gradually decreasing as the n SEL Pin to Set Either 4.1V or 4.2V/Cell (LTC1730-4) battery approaches a fully charged condition. A program- n Low-Battery Drain (1m A Max) when Input Supply Is mable timer ends the charge cycle. The end-of-charge Removed condition is indicated at the CHRG pin when the average n Battery Temperature Sensing and Charge charge current falls to C/10. Removing the input voltage Qualification puts the LTC1730 into a sleep mode, dropping the battery n Automatic Trickle Charge for Low-Battery current drain to less than 1m A (maximum). n Automatic Battery Refresh An external sense resistor limits the maximum charge current as a safety precaution against a user connecting a U wall adapter with the incorrect or no current limit. The APPLICATIO S internal MOSFET prevents reverse battery current from n Standalone Lithium-Ion Battery Charger flowing if the input voltage is shorted to ground, eliminat- n Handheld Computers ing the need for a blocking diode. n Cellular Telephones The LTC1730-4 is available in the 16-pin SSOP package and the LTC1730-4.2 is available in the 8-pin SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO 1A, Single Cell 4.2V Li-Ion Battery Charger (8-Pin Package) V = 4.5V TO 12V IN WITH 1A CURRENT LIMIT 2 R2 4.7 R1 V CC 10k R 1k SENSE C1 C3 R3 0.05 1F D3 LTC1730ES8-4.2 0.047F 4.1k 7 CHARGE STATUS GATE 3 0.022F CHRG 1 SENSE 8 6 NTC/SHDN BAT 1-CELL R4 Li-Ion 10k T BATTERY TIMER GND NTC* 54 C TIMER 0.1F *NTC: DALE NTHS-1206N02 1730 TA01 sn1730 1730fs 1 U ULTC1730-4/LTC1730-4.2 ABSOLUTE AXI U RATI GS (Note 1) Supply Voltage (V ) ............................................ 13.2V Operating Junction CC SENSE, GATE, BAT, Temperature Range (Note 2) .................. 40 C to 85 C TIMER, NTC/SHDN, SEL ............................ 0.3V to V Storage Temperature Range ................. 65 C to 150 C CC CHRG, ACPR, FAULT ..............................0.3V to 13.2V Lead Temperature (Soldering, 10 sec).................. 300 C TOP VIEW ORDER PART ORDER PART 1 GND* GND* 16 NUMBER NUMBER 2 BAT SENSE 15 LTC1730EGN-4 LTC1730ES8-4.2 3 NC** V 14 CC TOP VIEW 4 GATE ACPR 13 5 SEL FAULT 12 SENSE 1 8 BAT 6 NTC/SHDN CHRG 11 V 2 7 GATE CC 7 TIMER NC** 10 CHRG 3 6 NTC/SHDN GN PART MARKING S8 PART MARKING 8 GND* GND* 9 GND 4 5 TIMER 17304 173042 GN PACKAGE S8 PACKAGE 16-LEAD PLASTIC SSOP 8-LEAD PLASTIC SO * FOUR CORNER PINS ARE FUSED TO T = 125 C, q = 110 C/W JMAX JA INTERNAL DIE ATTACH PADDLE FOR HEAT SINKING. CONNECT THESE FOUR PINS TO EXPANDED PC LANDS FOR PROPER HEAT SINKING. ** NO INTERNAL CONNECTION T = 125 C, q = 90 C/W JMAX JA 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 CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Supply Voltage l 4.5 12 V CC I Supply Current Charger On Fast Charge Mode l 25 mA CC Shutdown: V = 0V l 25 mA NTC/SHDN Sleep Mode V = 4V l 1 m A BAT V Regulated Output Voltage LTC1730ES8-4.2 (5V V 12V) l 4.158 4.2 4.242 V BAT CC LTC1730EGN-4 (5V V 12V), SEL = GND l 4.059 4.1 4.141 V CC LTC1730EGN-4 (5V V 12V), SEL = V l 4.158 4.2 4.242 V CC CC I Maximum Charge Overcurrent R = 0.1W l 0.7 1 1.3 A MAX SENSE I Trickle Charge Current V = 2V 15 35 60 mA TRICKL BAT V Trickle Charge Trip Threshold 2.45 2.55 V TRICKL V Automatic Shutdown Threshold Voltage (V V ) Low to High 150 mV ASD CC BAT (Sleep Mode) (V V ) High to Low 0 mV CC BAT R Internal Switch On-Resistance V = 4V 0.35 W DS(ON) BAT V Shutdown Threshold Voltage NTC/SHDN Pin High to Low 50 mV SHDN sn1730 1730fs 2 U WWW