Datasheet LTC4012-3 (Analog Devices)

LTC4012-3 High Efficiency, Multi-Chemistry Battery Charger with PowerPath Control FeaTures DescripTion n
General Purpose Battery Charger Controller
The LTC®4012-3 is a constant-current/constant-voltage n
Efficient 550kHz Synchronous Buck PWM Topology
battery charger controller. It uses a synchronous quasi- n
±0.5% Output Float Voltage Accuracy
constant frequency PWM control architecture that will not n
Programmable Charge Current: 4% Accuracy
generate audible noise with ceramic bulk capacitors. Charge n
Programmable AC Adapter Current Limit:
current is set by external resistors and can be monitored
3% Accuracy
as an output voltage across the programming resistor. n
No Audible Noise with Ceramic Capacitors
With no built-in termination, the LTC4012-3 charges a n
INFET Low Loss Ideal Diode PowerPath™ Control
wide range of batteries under external control. n Wide Input Voltage Range: 6V to 28V The LTC4012-3 features ful y adjustable output voltage. For n Wide Output Voltage Range: 2V to 28V charge management and safety, the IC includes an input n Indicator Outputs for Charging, C/10 Current P-channel MOSFET ideal diode controller, battery (output) Detection and Input Current Limiting overvoltage protection, reverse charge current protection, n Analog Charge Current Monitor PWM soft-start and robust non-overlap control for an all n Micropower Shutdown N-channel MOSFET PWM power stage. n 20-Pin 4mm × 4mm × 0.75mm QFN Package The device includes AC adapter input current limiting, which applicaTions maximizes the charge rate for a fixed input power level. An external sense resistor programs the input current limit, n Notebook Computers and the ICL status pin indicates reduced charge current as n Portable Instruments a result of AC adapter current limiting. Ideal diode control n Battery Backup Systems at the adaptor input improves charger efficiency. 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 The CHRG status pin is active during all charging modes, are the property of their respective owners. Protected by U.S. Patents including 5723970. including special indication for low charge current. Typical applicaTion FROM 25mΩ ADAPTER POWER TO
Efficiency at DCIN = 20V
13V TO 20V 0.1µF SYSTEM 20µF 5.1k INFET CLP 100 10000 CLN 95 EFFICIENCY DCIN BOOST 0.1µF POWER LOSS (mW) 0.1µF TGATE 90 SW 85 POWER LOSS 1000 CHRG INTVDD 2µF TO/FROM ICL BGATE 6.8µH EFFICIENCY (%) MCU 80 SHDN GND VOUT = 12.3V 3.01k 75 RSENSE = 33mΩ ITH CSP RIN = 3.01k R 6.04k PROG = 26.7k LTC4012-3 33mΩ 70 100 0 0.5 1 1.5 2 2.5 3 0.1µF 3.01k CSN CHARGE CURRENT (A) BAT
PIN 5 NAME
PROG FBDIV 20µF 301k
PART GND ACP
26.7k 4.7nF + LTC4012 X VFB 12.3V LTC4012-3 X 4012-3 TA02 32.8k Li-Ion BATTERY 4012-3 TA01 40123fb Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Test Circuits Operation Applications Information Package Description Revision History Typical Application Related Parts