Features and Benefits

  • Input Current Limiting
  • 175s Charge Safety Timeout
  • 128mA Wake-Up Charge
  • Charges Any Chemistry Battery: Li+, NiCd, NiMH, Lead Acid, etc.
  • Intel SMBus 2-Wire Serial Interface
  • Compliant with Level 2 Smart Battery Charger Spec Rev 1.0
  • +8V to +28V Input Voltage Range
  • Up to 18.4V Battery Voltage
  • 11-Bit Battery Voltage Setting
  • ±0.8% Output Voltage Accuracy with Internal Reference
  • 3A (max) Battery Charge Current
  • 6-Bit Charge-Current Setting
  • 99.99% (max) Duty Cycle for Low-Dropout Operation
  • Load/Source Switchover Drivers
  • >97% Efficiency

Product Details

The MAX1645B is a high-efficiency battery charger capable of charging batteries of any chemistry type. It uses the Intel System Management Bus (SMBus) to control voltage and current-charge outputs.

When charging lithium-ion (Li+) batteries, the MAX1645B automatically transitions from regulating current to regulating voltage. The MAX1645B can also limit line input current so as not to exceed a predetermined current drawn from the DC source. A 175s charge safety timer prevents "runaway charging" should the MAX1645B stop receiving charging voltage/current commands.

The MAX1645B employs a next-generation synchronous buck control circuitry that lowers the minimum input-to-output voltage drop by allowing the duty cycle to exceed 99%. The MAX1645B can easily charge one to four series Li+ cells.


  • Notebook Computers
  • Personal Digital Assistants
  • Point-of-Sale Terminals

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.

Evaluation Kits (1)

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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.

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Lead Times

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