SMBus Level 2 Battery Charger with Remote Sense

Low-Cost SMBus Charger with Integrated Dual n-Channel FET Drivers Deliver Up to 8A Charge Current

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The MAX8731A is an SMBus™ programmable multi-chemistry battery charger. The MAX8731A uses a minimal command set to easily program the charge voltage, charge current, and adapter current limit.

The MAX8731A charges one to four Li+ series cells and delivers up to 8A charge current. The MAX8731A drives n-channel MOSFETs for improved efficiency and reduced cost. Low-offset current-sense amplifiers provide high accuracy with 10mΩ sense resistors.

The MAX8731A current-sense amplifiers provide high accuracy (3% at 3.5A) and also provide fast cycle-by-cycle current-mode control to protect against battery short circuit and system load transients.

The charger employs dual remote sense, which reduces charge time by measuring the feedback voltage directly at the battery, improving accuracy of initial transition into constant-voltage mode. The MAX8731A provides 0.5% battery voltage accuracy directly at the battery terminal.

The MAX8731A provides a digital output that indicates the presence of the AC adapter, as well as an analog output that indicates the adapter current within 4% accuracy.

The MAX8731A is available in a small 5mm x 5mm, 28-pin, thin (0.8mm) QFN package. An evaluation kit is available to reduce design time. The MAX8731A is available in a lead-free package.
MAX8731A: Typical Operating Circuit MAX8731A: Typical Operating Circuit Enlarge+

Key Features

  • 0.5% Battery Voltage Accuracy
  • 3% Input Current-Limit Accuracy
  • 3% Charge-Current Accuracy
  • SMBus 2-Wire Serial Interface
  • Cycle-by-Cycle Current Limit
    • Battery Short-Circuit Protection
    • Fast Response for Pulse Charging
    • Fast System-Load-Transient Response
  • Dual-Remote-Sense Inputs
  • Monitor Outputs for
    • Adapter Current (4% Accuracy)
    • AC Adapter Detection
  • 11-Bit Battery Voltage Setting
  • 6-Bit Charge-Current/Input-Current Setting
  • 8A (max) Battery Charger Current
  • 11A (max) Input Current
  • +8V to +26V Input Voltage Range
  • Charges Li+, NiMH, and NiCd Battery Chemistries


  • Medical Devices
  • Notebook Computers
  • Portable Equipment with Rechargeable Batteries
  • Tablet PCs
Part NumberLithium Ion CellsProtected VIN
Charging VIN
Charge Rate Set byMax. ICHG
Charge TerminationCharge RegulationOper. Temp.
maxmaxSee Notes
Current Limit
Max. Voltage
Smart Battery Control
Switchmode-40 to +85
$7.54 @1k
See All Battery Chargers (74)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX8731AEVKIT: Evaluation Kit/Evaluation System for the MAX8731A

Quality and Environmental Data

Product Reliability Reports: MAX8731A.pdf 
Lead-Free Package Tin (Sn) Whisker Reports
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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