Charger chips keep Li cells cool

Stand-alone linear battery charger supplies single-cell Li-ion/polymer batteries with up to 950mA without overheating the device or its surrounding components.

Linear Technology has introduced the LTC4095, a tiny, fully integrated, stand-alone linear battery charger for charging single-cell Li-ion/polymer batteries at up to 950mA without overheating the device or its surrounding components.

This fully featured USB-compatible IC offers digital high power select (charge current set to 100 or 20% of programmed value) and suspend mode input pins in addition to an NTC thermistor input, trickle charge, timer termination with C/10 detection and automatic recharge.

stand-alone operation eliminates the need for a microprocessor to terminate charging.

A complete charger solution with the LTC4095 requires only two discrete components (input capacitor and a charge current program resistor), and fits into a compact form factor with its low profile (0.75mm) 8-lead 2 x 2mm DFN package.

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

The LTC4095 requires no external MOSFET, sense resistor or blocking diode.

A patented thermal regulation scheme prevents the junction temperature of the IC from exceeding 105C by reducing charge current during high power or high ambient temperature operation.

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

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 suspend mode, the supply current is only 11uA and battery drain current is less included 2uA.

LTC4095 also features four charge indication states including blinking, bad battery detection, a charge current monitor output for gas gauging, a 4.2V 0.6% accurate float voltage, and 5% charge accuracy.

The LTC4095 is rated for operation from -40 to +85C.

Pricing starts at US $1.15 each in 1000-piece quantities.

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