DESCRIPTION
The LTC®1558 is a backup battery controller that provides all the functions necessary to implement a backup power supply using a single NiCd cell. It includes a 1.2V boost converter, an intelligent 2-stage battery charger, auto matic backup switching and a microprocessor reset generator. The boost converter uses a synchronous switching architecture to achieve a typical efficiency of 70%, ensuring maximum backup lifetime from a small NiCd cell.

FEATURES
■ Complete Battery Backup System in an SO-8, 16-Pin GN or SO Package
■ Generates Adjustable Backup Voltage from a Single 1.2V NiCd Button Cell
■ Automatic Main Supply to Backup Switching
■ Minimum 100mW Output Power
■ Automatic Fast Recharge of NiCd Battery
■ Programmable NiCd Trickle Charge Current
■ Smart NiCd Charger Minimizes Recharge Time and Maximizes System Efficiency After Backup
■ On-Chip Power-On Reset
■ Pushbutton Reset Input
■ Reset Assertion Guaranteed at VCC= 1V
■ Short-Circuit Protection
■ Thermal Limiting

APPLICATIONS
■ Notebook Computers
■ Palmtop Computers/PDAs
■ Portable Instruments
■ Battery-Powered Systems