* Question

What are the main features of the MAXl773/MAXl773A power-selector chip?

* Answer

The MAX1773/MAX1773A are advanced power-selector chips from Maxim Integrated, designed primarily for portable systems such as notebooks and handheld devices that require seamless power source transitions. Here are their main features:

Dual Power-Source Management

Automatic Power-Source Selection: These chips intelligently choose between an AC adapter and a battery based on availability and priority.

Ideal Diode Behavior: They emulate ideal diode operation to prevent reverse current and minimize voltage drops during source switchover.

Integrated High-Side MOSFET Control

Controls external N-channel MOSFETs, which are used as high-side switches for both the AC adapter and the battery paths.

Ensures low R_DS(ON) operation and efficient power flow.

Smart Control & Protection Features

Reverse-Current Protection: Prevents current from flowing back into the adapter or battery.

Input Overvoltage Protection: Shuts off power path if the adapter voltage exceeds a safe level.

Undervoltage Lockout (UVLO): Disables outputs if input voltage is too low, protecting system integrity.

Thermal Protection: Includes thermal shutdown for safety.

Programmability & Status Feedback

Adapter Detection Threshold: Can be configured via resistor divider.

ACOK (AC Adapter OK) Output: Open-drain status pin to indicate presence of a valid adapter.

Power-Path Prioritization: Automatically prioritizes adapter over battery to preserve battery life.

Compact & Efficient Design

Works in systems with:

Adapter voltages typically up to 26V

Battery voltages from 2.5V to 24V

Available in space-saving TQFN or QSOP packages, making them ideal for mobile designs.

Applications

Notebook and sub-notebook computers

Portable instrumentation

Battery-powered consumer electronics

Systems needing seamless transition between power sources