The LTC4065L is a fully integrated standalone linear battery charger that charges single coin cell Li-Ion batteries up to 250 mA without overheating the device or surrounding components. Developed by Linear Technology Corp., the IC offers a 4.2-V +/-0.5% accurate float voltage, 5% charge current accuracy, timer termination, and C/10 detection. All that gets packed into a miniature 2 by 2-mm DFN package. A complete solution requires just two discrete components (an input capacitor and a charge current program resistor).
The LTC4065L requires no external MOSFET, sense resistor, or blocking diode. The part's thermal regulation scheme prevents its junction temperature from exceeding 115°C by reducing charge current during high power or high ambient temperature operation. Other features include a charge current monitor output for charge termination, recharge, trickle charging, and charge status indication. Charge current is adjustable with a standard off-the-shelf resistor. The device is designed to work with supplies up to 5.5 V, including those within USB specs and from 5-V wall adapters. During shutdown, the supply current is 20 ΜA and battery drain current is below 1 ΜA.
Prices start at $1.10 each in 1000-piece quantities. For more information, visit www.linear.com.