Datasheet LT3651-4.1, LT3651-4.2 (Analog Devices)

LT3651-4.1/LT3651-4.2 Monolithic 4A Wide Input 1 Cell Li-Ion Battery Charger
FEATURES DESCRIPTION
n
Wide Input Voltage Range: Up to 32V
The LT®3651 is a 1 cell 4A Li-Ion/Polymer battery charger
(40V Absolute Maximum)
that operates with input voltages up to 32V. An efficient n
Programmable Charge Current Up to 4A
monolithic average current mode synchronous switching n
Selectable C/10 or Onboard Timer Termination
regulator provides constant current, constant voltage n
Dynamic Charge Rate Programming/Soft-Start
charging with programmable maximum charge current. n
Programmable Input Current Limit
A charging cycle starts with battery insertion or when n 0.5% Float Voltage Accuracy the battery voltage drops 2.5% below the float voltage. n 7.5% Charge Current Accuracy Charger termination is selectable as either charge current n 4% C/10 Detection Accuracy or internal safety timer timeout. Charge current termina- n NTC Resistor Temperature Monitor tion occurs when the charge current falls to one-tenth n Auto-Recharge at 97.5% Float Voltage the programmed maximum current (C/10). Timer based n Auto-Precondition <70% Float Voltage termination is typically set to three hours and is user pro- n Bad Battery Detection with Auto-Reset grammable (charging continues below C/10 until timeout). n Average Current Mode, Synchronous Switcher Once charging is terminated, the LT3651 supply current n User Programmable Frequency drops to 85µA into a standby mode. n Low Profile (0.75mm) 5mm × 6mm 36-Pin The LT3651 offers several safety features. A discharged QFN Package battery is preconditioned with a small trickle charge and
APPLICATIONS
generates a signal if unresponsive. A thermistor monitors battery temperature, halting charging if out of range. Ex- n Industrial Handheld Instruments cessive die temperature reduces charge current. Charge n 12V to 24V Automotive and Heavy Equipment current is also reduced to maintain constant input current n Desktop Cradle Chargers to prevent excessive input loading. n Notebook Computers The LT3651 is available in a 5mm × 6mm 36-pin QFN L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the package. property of their respective owners.
TYPICAL APPLICATION Efficiency, Power Loss vs DCIN 6.5V to 32V Single Cell 4A Charger
86 4.4 V TO BAT = 3.9 DC E IN SYSTEM FF 6.5V TO 32V 85 4.0 100k 22µF LOAD 10V CLP CLN V Si7611DN IN POWER LOSS (W) SHDN SW 84 3.6 100k ACPR 1µF FAULT BOOST 6.5µH 83 3.2 CHRG WÜRTH 744314650 LT3651-4.2 1N5819 SENSE EFFICIENCY (%) 82 2.8 RT 24mΩ 301k 81 2.4 PLOSS TIMER BAT + NTC 100µF BATTERY 80 2.0 ILIM RNG/SS GND 365142 TA01a 5 10 15 20 25 30 DCIN (V) 365142 TA01b 365142ff For more information www.linear.com/LT3651-4.1 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Pin Functions Block Diagram Operation Applications Information Typical Applications Revision History Typical Application Related Parts