LTC4008 4A, High Efficiency, Multi-Chemistry Battery Charger FEATURES DESCRIPTION n General Purpose Charger Controller The LTC 4008 is a constant-current/constant-voltage n High Conversion Efficiency: Up to 96% charger controller. The PWM controller uses a synchro- n Output Currents Exceeding 4A nous, quasi-constant frequency, constant off-time archi- n 0.8% Voltage Accuracy tecture that will not generate audible noise even when n AC Adapter Current Limiting Maximizes using ceramic capacitors. Charging current is program- Charge Rate* mable with a sense resistor and programming resistor to n Thermistor Input for Temperature Qualified Charging 4% typical accuracy. Charging current can be monitored n Wide Input Voltage Range: 6V to 28V as a voltage across the programming resistor. An external n Wide Output Voltage: 3V to 28V resistor divider and precision internal reference set the n 0.5V Dropout Voltage Maximum Duty Cycle: 98% final float voltage. n Programmable Charge Current: 4% Accuracy The LTC4008 includes a thermistor sensor input that will n Indicator Outputs for Charging, C/10 Current suspend charging if an unsafe temperature condition is Detection, AC Adapter Present, Input Current detected and will automatically resume charging when Limiting and Faults battery temperature returns to within safe limits a FAULT n Charging Current Monitor Output pin indicates this condition. A FLAG pin indicates when n Available in a 20-Pin Narrow SSOP Package charging current has decreased below 10% of the pro- grammed current. An external sense resistor programs APPLICATIONS AC adapter current limiting. The I pin indicates when the CL n Notebook Computers charging current is being reduced by input current limiting n Portable Instruments so that the charging algorithm can adapt. n Battery Backup Systems All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents including 5723970. TYPICAL APPLICATION 12.3V, 4A Li-Ion Charger INPUT SWITCH DCIN 0V TO 28V 0.1F 140k* LTC4008 V BATMON DCIN LOGIC 0.1F 0.02 100k 100k V INFET FB SYSTEM 4.99k I I CLP CL CL LOAD 20F ACP ACP/SHDN CLN FAULT FAULT TGATE Q1 10H 0.025 FLAG FLAG BGATE 32.4k Li-Ion Q2 NTC PGND 20F BATTERY R CSP T 3.01k 15k* I BAT TH THERMISTOR 3.01k GND PROG 150k 6.04k 10k CHARGING NTC CURRENT 0.47F MONITOR 0.12F 26.7k Q1: Si4431BDY 0.0047F Q2: FDC645N NOTE: * 0.25% TOLERANCE 4008 TA01 ALL OTHER RESISTORS ARE 1% TOLERANCE Rev C 1 Document Feedback For more information www.analog.comLTC4008 ABSOLUTE MAXIMUM RATINGS (Note 1) Voltage from DCIN, CLP, CLN to GND ......... +32V/0.3 V CLP to CLN ..........................................................+0.5V PGND with Respect to GND ...................................0.3V Operating Ambient Temperature Range CSP, BAT to GND .......................................... +28V/0.3V (Note 4) ...............................................40C to 85C V , R to GND ............................................... +7V/0.3V Operating Junction Temperature ............ 40C to 125C FB T NTC ...............................................................+10V/0.3V Storage Temperature Range .................. 65C to 150C ACP/SHDN, FLAG, FAULT, I ...................... +32V/0.3V Lead Temperature (Soldering, 10 sec) ...................300C CL PIN CONFIGURATION LTC4008 LTC4008-1* TOP VIEW TOP VIEW DCIN 1 20 INFET DCIN 1 20 NC I 2 19 BGATE I 2 19 BGATE CL CL ACP/SHDN 3 18 PGND SHDN 3 18 PGND R 4 17 TGATE R 4 17 TGATE T T FAULT 5 16 CLP FAULT 5 16 CLP GND 6 15 CLN GND 6 15 CLN V 7 14 FLAG V 7 14 FLAG FB FB NTC 8 13 BATMON NTC 8 13 BATMON I 9 12 BAT I 9 12 BAT TH TH PROG 10 11 CSP PROG 10 11 CSP GN PACKAGE GN PACKAGE 20-LEAD NARROW PLASTIC SSOP 20-LEAD NARROW PLASTIC SSOP T = 125C, = 90C/W T = 125C, = 90C/W JMAX JA JMAX JA *The LTC4008EGN-1 does not have the Input FET function ORDER INFORMATION