1. Products
  2. Power Management
  3. Battery Management
  4. Battery Charger IC
  5. Switching Battery Chargers
  6. MAX1909


Features and Benefits

  • Precise Measurement Improves Safety and Performance
    • ±0.5% Accurate Charge Voltage (0°C to +85°C)
    • ±3% Accurate Input Current Limiting
    • ±5% Accurate Charge Current
    • Analog Inputs Control Charge Current and Charge Voltage
  • Charge Any Battery Chemistry: Li+, NiCd, NiMH, Lead Acid, etc.
    • Up to 17.65V (max) Battery Voltage
    • Maximum 28V Input Voltage
    • Programmable Charge Current > 4A
  • Intelligent AC Adapter Interface Makes Design Easier
    • Automatic System Power/Source Selection
    • Analog Monitoring of Current Drawn from AC Input Source
    • Digital Output Indicates AC Adapter Presence
  • Greater than 95% Efficiency Extends Battery Life

Product Details

The MAX1909/MAX8725 highly integrated control ICs simplify construction of accurate and efficient multichemistry battery chargers. The MAX1909/MAX8725 use analog inputs to control charge current and voltage, and can be programmed by a host microcontroller (µC) or hardwired. High efficiency is achieved through use of buck topology with synchronous rectification.

The maximum current drawn from the AC adapter is programmable to avoid overloading the AC adapter when supplying the load and the battery charger simultaneously. The MAX1909/MAX8725 provide a digital output that indicates the presence of an AC adapter, and an analog output that monitors the current drawn from the AC adapter. Based on the presence or absence of the AC adapter, the MAX1909/MAX8725 automatically select the appropriate source for supplying power to the system by controlling two external p-channel MOSFETs. Under system control, the MAX1909/MAX8725 allow the battery to undergo a relearning or conditioning cycle in which the battery is completely discharged through the system load and then recharged.

The MAX1909 includes a conditioning charge feature while the MAX8725 does not. The MAX1909/MAX8725 are available in space-saving 28-pin, 5mm x 5mm thin QFN packages and operate over the extended -40°C to +85°C temperature range. The MAX1909/MAX8725 are now available in lead-free packages.


  • Handheld Data Terminals
  • 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.

Evaluation Kits (1)

Product Recommendations

MAX1909 Companion Parts

Recommended Related Parts

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
MAX1909ETI+ Material Declaration Reliability Data 28-LFCSP-5X5X0.75
MAX1909ETI+T Material Declaration Reliability Data 28-LFCSP-5X5X0.75
Wafer Fabrication Data MAX1909 Reliability Data

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Lead Times

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



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