LTC4007-1 4A, High Efficiency, Li-Ion Battery Charger Fea T Descrip T n Charger Controller for 3- or 4-Cell The LTC 4007-1 is a constant-current/constant-voltage Lithium-Ion Batteries charger controller for 3- or 4-cell lithium-ion batteries. n High Conversion Efficiency: Up to 96% The PWM controller uses a synchronous, quasi-constant n Output Currents Exceeding 4A frequency, constant off-time architecture that will not n 0.8% Charging Voltage Accuracy generate audible noise even when using ceramic capaci- n Built-In Charge Termination for Li-Ion Batteries tors. Charging current is programmable to 4% accuracy n AC Adapter Current Limiting Maximizes Charge Rate* using a programming resistor. Charging current can also be n Thermistor Input for Temperature Qualified Charging monitored as a voltage across the programming resistor. n Wide Input Voltage Range: 6V to 28V The output float voltage is pin programmed for cell count n 0.5V Dropout Voltage Maximum Duty Cycle: 98% (3 cells or 4 cells) and chemistry (4.2V/4.1V). A timer, pro- n Programmable Charge Current: 4% Accuracy grammed by an external resistor, sets the total charge time. n Indicator Outputs for Charging, C/10 Current The LTC4007-1 includes a thermistor input, which Detection, AC Adapter Present, Low Battery, Input suspends charging if an unsafe temperature condition Current Limiting and Faults n is detected. If the cell voltage is less than 3.25V, a low- Charging Current Monitor Output n battery indicator asserts and can be used to program a Available in a 24-Pin 4mm 5mm QFN Package trickle charge current to safely charge depleted batteries. a T The FAULT pin is also asserted and charging terminates if the low-battery condition persists for more than 1/4 of n Notebook Computers the total charge time. n Portable Instruments L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n Battery-Backup Systems NoR is a trademark of Linear Technology Corporation. All other trademarks are the SENSE property of their respective owners. n Li-Ion Chargers Protected by U.S. Patents including 5723970. Typical a T 12.6V, 4A Li-Ion Battery Charger INPUT SWITCH DCIN 0V TO 28V LOW BATTERY 0.1F AUTO THRESHOLD (Per Cell) 4.99k PART RESTART (4.2V/4.1V) 3C4C DCIN V LOGIC LTC4007-1 NO 3.25V/3.173V 15nF 0.025 100k 100k 100k CHEM INFET LTC4007 YES 2.5V/2.44V SYSTEM LOBAT LOBAT CLP LOAD LTC4007-1 I I CLN CL CL 20F ACP ACP TGATE Q1 10H 0.025 SHDN SHDN BGATE Li-Ion Q2 FAULT FAULT PGND BATTERY 20F CHG CHG CSP 3.01k FLAG FLAG BAT 32.4k 3.01k NTC PROG CHARGING CURRENT R ITH T THERMISTOR MONITOR 0.0047F 0.47F 6.04k GND 10k Q1: Si4431BDY NTC Q2: FDC645N TIMING RESISTOR 26.7k 309k 0.12F (~2 HOURS) 40071 TA01 40071fa 1 For more information www.linear.com/LTC4007-1 ion pplica ions pplica ion uresLTC4007-1 a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW Voltage from DCIN, CLP, CLN to GND ......... +32V/0.3V PGND with Respect to GND .................................. 0.3V CSP, BAT to GND ......................................... +28V/0.3V 24 23 22 21 20 ACP 1 19 CHEM, 3C4C, R to GND ................................ +7V/0.3V NC T R 2 18 PGND T NTC .............................................................. +10V/0.3V FAULT 3 17 TGATE ACP, SHDN, CHG, FLAG, GND 4 25 16 CLN FAULT, LOBAT, I ........................................ +32V/0.3V CL 3C4C 5 15 CLP CLP to CLN ............................................................0.5V LOBAT 6 14 FLAG Operating Ambient Temperature Range 7 NTC 13 CHEM 8 9 10 11 12 (Note 4) ............................................. 40C to 85C Operating Junction Temperature ........... 40C to 125C Storage Temperature Range .................. 65C to 125C UFD PACKAGE 24-LEAD (4mm 5mm) PLASTIC QFN T = 125C, = 90C/W JMAX JA EXPOSED PAD (PIN 25), GND AND PGND SHOULD BE CONNECTED TOGETHER WITH A LOW OHMIC CONNECTION