Datasheet LTC4012, LTC4012-1, LTC4012-2 (Analog Devices)

LTC4012/ LTC4012-1/LTC4012-2 High Efficiency, Multi-Chemistry Battery Charger with PowerPath Control Features Description n
General Purpose Battery Charger Controller
The LTC4012 is a constant-current/constant-volt- n
Efficient 550kHz Synchronous Buck PWM Topology
age battery charger controller. It uses a synchronous n
±0.5% Output Float Voltage Accuracy
quasi-constant frequency PWM control architecture n
Programmable Charge Current: 4% Accuracy
that will not generate audible noise with ceramic bulk n
Programmable AC Adapter Current Limit:
capacitors. Charge current is set by external resis-
3% Accuracy
tors and can be monitored as an output voltage. n
No Audible Noise with Ceramic Capacitors
With no built-in termination, the LTC4012 family charges n
INFET Low Loss Ideal Diode PowerPath™ Control
a wide range of batteries under external control. n Wide Input Voltage Range: 6V to 28V The LTC4012 features ful y adjustable output voltage, while n Wide Output Voltage Range: 2V to 28V the LTC4012-1 and LTC4012-2 can be pin-programmed for n Indicator Outputs for AC Adapter Present, Charging, Lithium-Ion/Polymer battery packs of 1-, 2-, 3- or 4-series C/10 Current Detection and Input Current Limiting cells. The LTC4012-1 provides output voltage of 4.1V/cell n Analog Charge Current Monitor and the LTC4012-2 is a 4.2V/cell version. n Micropower Shutdown n 20-Pin 4mm × 4mm × 0.75mm QFN Package The device includes AC adapter input current limiting, which maximizes charge rate for a fixed input power level. An applications external sense resistor programs the input current limit, and the ICL status pin indicates reduced charge current as n Notebook Computers a result of AC adapter current limiting. Ideal diode control n Portable Instruments at the adaptor input improves charger efficiency. n Battery Backup Systems The CHRG status pin is active during all charging modes, L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks including special indication for low charge current. are the property of their respective owners. Protected by U.S. Patents including 5723970. typical application FROM 25mΩ POWER TO
Efficiency at DCIN = 20V
ADAPTER 13V TO 28V 0.1µF SYSTEM 20µF 5.1k 100 10000 INFET CLP EFFICIENCY CLN 95 DCIN BOOST POWER LOSS (mW) 0.1µF 0.1µF 90 TGATE ACP POWER LOSS SW 85 1000 CHRG INTVDD TO/FROM 2µF EFFICIENCY (%) MCU 80 ICL BGATE 6.8µH VOUT = 12.3V R SHDN GND 75 SENSE = 33mΩ R 3.01k IN = 3.01k ITH CSP RPROG = 26.7k 6.04k 70 100 LTC4012 33mΩ 0 0.5 1 1.5 2 2.5 3 0.1µF 3.01k CHARGE CURRENT (A) CSN BAT
PIN NAME
PROG FBDIV 20µF
PART INFET DCDIV
301k 26.7k 4.7nF + LTC4009 X VFB 12.3V LTC4012 X 4012 TA02 32.8k Li-Ion BATTERY 4012 TA01 4012fa Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Test Circuits Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts