Features and Benefits

  • Wide Input Voltage Range: 9V to 32V (40V Absolute Maximum)
  • Programmable Charge Current Up to 4A
  • Selectable C/10 or Onboard Timer Termination
  • Dynamic Charge Rate Programming/Soft-Start
  • Programmable Input Current Limit
  • ±0.5% Float Voltage Accuracy
  • ±7.5% Charge Current Accuracy
  • ±4% C/10 Detection Accuracy
  • NTC Resistor Temperature Monitor
  • Auto-Recharge at 97.5% Float Voltage
  • Auto-Precondition at <70% Float Voltage
  • Bad Battery Detection with Auto-Reset
  • Average Current Mode, Synchronous Switcher
  • User Programmable Frequency
  • Low Profile (0.75mm) 5mm × 6mm 36-Lead QFN Package

Product Details

The LT3651-8.2/LT3651-8.4 are 2-cell, 4A Li-Ion/Polymer battery chargers that operate over a 9V to 32V input voltage range. An efficient monolithic average current mode synchronous switching regulator provides constant current, constant voltage charging with programmable maximum charge current. A charging cycle starts with battery insertion or when the battery voltage drops 2.5% below the float voltage. Charger termination is selectable as either charge current or internal safety timer timeout. Charge current termination occurs when the charge current falls to one-tenth the programmed maximum current (C/10). Timer based termination is typically set to three hours and is user programmable (charging continues below C/10 until timeout). Once charging is terminated, the LT3651-8.2/LT3651-8.4 supply current drops to 85μA into a standby mode.

The LT3651-8.2/LT3651-8.4 offer several safety features. A discharged battery is preconditioned with a small trickle charge and generates a signal if unresponsive. A thermistor monitors battery temperature, halting charging if out of range. Excessive die temperature reduces charge current. Charge current is also reduced to maintain constant input current to prevent excessive input loading. The LT3651-8.2/LT3651-8.4 are available in a 5mm × 6mm 36-lead QFN package.

Float Voltage
LT3651-4.1 4.1V
LT3651-4.2 4.2V
LT3651-8.2 8.2V
LT3651-8.4 8.4V


  • Industrial Handheld Instruments
  • 12V to 24V Automotive and Heavy Equipment
  • Desktop Cradle Chargers
  • Notebook Computers

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (2)

Tools & Simulations


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Product Recommendations

LT3651-8.2 Companion Parts

Recommended Related Parts

Design Resources

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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.