MAX1538

PRODUCTION

Power-Source Selector for Dual-Battery Systems

Selector Provides Power-Source Control for Dual-Battery Systems, Minimizes System Cost

Data Sheet (Rev. 0) Product Selection Table

Part Models: 2
1ku List Price: Starting From $3.96

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Overview

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)

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. The MAX1538 includes analog comparators to detect AC/airline-adapter presence and determine battery undervoltage. Fast analog circuitry allows the device to switch between power sources to implement a break-before-make time, which allows hot swapping of battery packs. The MAX1538 independently performs power-source monitoring and selection, freeing the system power-management µP for other tasks. This simplifies the development of µP power-management firmware and allows the µP to enter standby, reducing system power consumption.

The MAX1538 supports “relearn mode,” which allows the system to measure and fully utilize battery capacity. In this state, the part allows the selected battery to be discharged even when an AC adapter is present. The MAX1538 can also be used to power the system in an aircraft. On detecting an airline adapter, the MAX1538 automatically disables charging or discharging of battery packs and only allows the system to be powered from the adapter.

The MAX1538 is available in a space-saving 28-pin thin QFN package with a maximum footprint of 5mm x 5mm.

Applications

Dual-Battery Portable Equipment
Internet Tablets
Notebook and Subnotebook Computers

Part Models: 2
1ku List Price: Starting From $3.96

Documentation

Data Sheet 1

MAX1538: Power-Source Selector for Dual-Battery Systems Data Sheet (Rev.0) 02/18/2004

Reliability Data 1

MAX1538 Reliability Data 01/12/2023

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
MAX1538ETI+	28-LFCSP-5X5X0.75	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
MAX1538ETI+T	28-LFCSP-5X5X0.75	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Evaluation Kits

Evaluation Kit for the MAX1538

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Features and Benefits

4.75V to 28V AC-Adapter Input Range
Up to 10A Steering Capability
P-Channel MOSFET Steering Switches
Adjustable Battery Minimum Voltage Level
Adjustable Airline/AC-Adapter Detection Voltages
Manual-or Computer-Controlled Interface
On-Board Status LEDs
Surface-Mount Components
Fully Assembled and Tested

Product Details

The MAX1538 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that routes charge and discharge currents between two battery packs, a battery charger, and an AC-adapter power source. The circuit uses a MAX1538 IC in a 28-pin thin QFN package and is configured for a 4.75VDC to 28VDC AC-adapter input range.

The EV kit uses eight P-channel MOSFETs to steer current between the power sources and the load. The battery minimum voltage level sets the threshold for battery undervoltage conditions and can be adjusted from 4.65V to 13.0V.