2A Synchronous Buck Li-Ion Charger

The LTC4001-1 is a 2A Li-Ion battery charger intended for 5V wall adapters. It utilizes a 1.5MHz synchronous buck converter topology to reduce power dissipation during charging. Low power dissipation, an internal MOSFET and sense resistor allow a physically small charger that can be embedded in a wide range of handheld applications. The LTC4001-1 includes complete charge termination circuitry, automatic recharge and a ±1% 4.1V float voltage. Input short-circuit protection is included so no blocking diode is required.

This 4.1V version of the standard LTC4001 is intended for applications which will be operated or stored above approximately 60°C. Under these conditions, the reduced float voltage will trade-off initial cell capacity for the benefit of increased capacity retention over the life of the battery. A reduced float voltage also minimizes swelling in prismatic and polymer cells, and avoids open CID (pressure fuse) in cylindrical cells.

Battery charge current, charge timeout and end-of-charge indication parameters are set with external components. Additional features include shorted cell detection, temperature qualified charging and overvoltage protection. The LTC4001-1 is available in a low profile (0.75mm) 16-lead (4mm × 4mm) QFN package.

Float Voltage

LTC4001

4.2V

LTC4001-1

4.1V

Applications

* Handheld Battery-Powered Devices

* Handheld Computers

* Charging Docks and Cradles

* Digital Cameras

* Smart Phones

* Low Power Dissipation

* 2A Maximum Charge Current

* No External MOSFETs, Sense Resistor or Blocking Diode Required

* Remote Sensing at Battery Terminals

* Programmable Charge Termination Timer

* Preset 4.1V Float Voltage with ±0.5% Accuracy