1. Products
  2. Power Management
  3. Battery Management
  4. Battery Fuel Gauge and Coulomb Counter
  5. MAX1538


Features and Benefits

  • 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)

Product Details

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.


  • Dual-Battery Portable Equipment
  • Internet Tablets
  • Notebook and Subnotebook Computers

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Design Resources

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 Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
MAX1538ETI+ Material Declaration Reliability Data 28-LFCSP-5X5X0.75
MAX1538ETI+T Material Declaration Reliability Data 28-LFCSP-5X5X0.75
Wafer Fabrication Data MAX1538 Reliability Data

Sample & Buy

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Buy Now Pricing

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List Pricing

(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

Please see the latest communication from our CCO regarding lead times.



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