General Description

The MAX1538 selector provides power-source control for dual-battery systems. The device selects between an AC adapter and dual batteries based on the presence of the three power sources and the state of charge of each battery.

Features

♦ Automatically Detects and Responds to

   Low-Battery Voltage Condition

   Battery Insertion and Removal

   AC-Adapter Presence

   Airline-Adapter Presence

♦ Step-Down and Step-Up Charger Compatibility

♦ Fast Break-Before-Make Selection

   Allows Hot Swapping of Power Sources

   No External Schottky Diodes Needed

♦ 50µA Maximum Battery Quiescent Current

♦ Implements Battery Capacity Relearning

♦ Allows Usage of Aircraft Supply

♦ Direct Drive of P-Channel MOSFETs

♦ Simplifies Power-Management µP Firmware

♦ 4.75V to 28V AC-Adapter Input Voltage Range

♦ Small 28-Pin Thin QFN Package (5mm x 5mm)