General Description

The MAX8568A/MAX8568B backup-battery-management ICs are complete charging and backup switchover control solutions for PDAs, Smart Phones, and other smart portable devices. They charge both NiMH and rechargeable lithium battery types and feature programmable charge current and termination voltage. Separate optimized charge algorithms for both lithium and NiMH cells are included on-chip.

The MAX8568A/MAX8568B also manage backup switchover from a primary power source. An accurate on chip voltage detector monitors the main supply and backs up two system supplies (typically I/O and memory) when main power falls. On-chip drivers switch external MOSFETs to disconnect the main supply from the system loads so the backup source is not drained.

Low-voltage backup cells can be stepped up by an on chip synchronous-rectified, low-quiescent-current boost converter. Additionally, a low-quiescent-current LDO generates a second backup voltage. The MAX8568A LDO is preset to 2.5V while the MAX8568B LDO is preset to 1.8V. Both devices are supplied in 16-pin 3mm x 3mm thin QFN packages rated for -40°C to +85°C operation.

Features

♦ Automatically Manage All Backup Switchover Functions

♦ Charge Both NiMH and Rechargeable Lithium Backup Batteries

♦ On-Chip Battery Boost Converter for 1-Cell NiMH

♦ Two Backup Output Voltages

♦ Programmable Charge Current

♦ Programmable Charge Voltage Limit

♦ Low 17µA Operating Current in Backup Mode

♦ Eliminate Many Discrete Components

♦ Tiny 3mm x 3mm Thin QFN Package

Applications

   PDAs and PDA Phones

   Smart Phones

   DSCs and DVCs

   Palmtops and Wireless Handhelds

   Internet Appliances and Web-Books