Date: 19/08/2010

32V, 4A synchronous step-down battery charger IC for Li-ion/Polymer batteries

Linear Technology has introduced LT3651-4.2, a 4A monolithic synchronous buck (step-down) type battery charger for 1-cell Li-Ion/Polymer batteries. The LT3651-4.2 accepts inputs in the range of 32V to 40V. Charge current is programmable and dynamically adjustable up to 4A.

The key features inlcude user-selectable timer or C/10 termination requires no external microcontroller, and does not require external high-precision resistors to set the float voltage.
Applications suggested are industrial handheld instruments, 12V to 24V automotive and heavy equipment applications, desktop cradle chargers and notebook or tablet computers.

The key specs inlcude programmable switching frequency of 200kHz to 1MHz, final float voltage accuracy is ±0.5%, charge current accuracy is ±7.5% and C/10 detection accuracy is ±4%. Once charging is terminated, the LT3651-4.2 automatically enters a low current standby mode which reduces the input supply current to 80uA. In shutdown, the input bias current is reduced to 15uA. The LT3651-4.2 maximizes battery life during all non-charging periods by draining <1uA from the battery. For safety and autonomous charge control, the device includes automatic restart and preconditioning, a thermistor input for temperature-qualified charging, programmable input current limit, bad battery detection and binary coded status output pins.

Package: 0.75mm, 36-pin 5mm x 6mm QFN

Operating temperature range: –40°C to 125°C.

Price: Each $4.13 and $4.75 each, respectively, in 1,000-piece quantities.

Availability: Two-cell 8.2V and 8.4V options and a one-cell 4.1V version are planned for release within the next 2-3 months