Charger chip keeps its cool

A tiny fully integrated stand-alone linear battery charger can charge a single-cell Li-ion battery at up to 750mA without overheating the device or surrounding components.

Linear Technology has introduced the LTC4069, a tiny fully integrated stand-alone linear battery charger that can charge a single-cell Li-ion battery at up to 750mA without overheating the device or surrounding components.

This full-featured IC offers timer termination, recharge, trickle charge, NTC thermistor input and C/10 detection, and is housed in a miniature 2 x 2mm DFN package.

A complete charger solution requires only four discrete components (input capacitor, NTC thermistor, bias resistor, and a charge current program resistor) and fits into a compact form factor.

Applications include digital still cameras, portable point-of-sale and diagnostic equipment, cellphones, wireless headsets, media players and USB-equipped handheld devices.

The LTC4069 requires no external MOSFET, sense resistor or blocking diode.

A patented thermal regulation scheme prevents the junction temperature of the IC from exceeding 115C by reducing charge current during high power or high ambient temperature operation.

The NTC thermistor input may be used for temperature-qualified charging.

Other features of the LTC4069 include a charge current monitor output for gas gauging, a 4.2V 0.5% accurate float voltage, and 5% charge accuracy.

Charge current is adjustable with a standard off-the-shelf resistor.

The device is designed to work with supplies up to 5.5V, including those within USB specifications and from 5V wall adapters.

During shutdown, the supply current is only 20uA and battery drain current is less than 1uA.

The LTC4069 is rated for operation from -40 to +85C.

Pricing starts at $1.10 each in 1000-piece quantities.

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