Features and Benefits

  • Complete Linear Charger Controller for 1-Cell Lithium-Ion Batteries
  • Preset Charge Voltage with 1% Accuracy
  • 4.5V to 12V Input Voltage Range
  • Programmable Charge Current
  • C/10 Charge Current Detection Output
  • Programmable Charge Termination Timer
  • Small, Thin 10-Pin MSOP Package
  • Select Pin to Charge Either 4.1V or 4.2V Cells (LTC1732-4)
  • Automatic Sleep Mode When Input Supply is Removed (Only 7µA Battery Drain)
  • Automatic Trickle Charge of Low Voltage Cells
  • Programmable for Constant-Current-Only Mode
  • Battery Insertion Detect
  • Input Supply (Wall Adapter) Detection Output
  • 4.05V Recharge Threshold for 4.2V Cells (LTC1732-4.2)
  • 3.8V Recharge Threshold for 4.1V or 4.2V Cells (LTC1732-4)

Product Details

The LTC1732 is a complete constant-current/constant-voltage linear charge controller for lithium-ion (Li-Ion) batteries. Nickel-cadmium (NiCd) and nickel metal-hydride (NiMH) batteries can also be charged with constant current using external termination. Charge current can be programmed with 7% (max) accuracy using external sense and program resistors. An internal resistor divider and precision reference set the final float voltage with 1% accuracy. The SEL pin allows users to charge either 4.1V or 4.2V cells.

When the input supply is removed, the LTC1732 automatically enters a low current sleep mode, dropping the battery drain current to 7µA. An internal comparator detects the end-of-charge (C/10) condition while a programmable timer, using an external capacitor, sets the total charge time. Fully discharged cells are automatically trickle charged at 10% of the programmed current until cell voltage exceeds 2.457V.

The LTC1732 begins a new charge cycle when a discharged battery is connected to the charger or when the input power is applied. In addition, if the battery remains connected to the charger and the cell voltage drops below 3.8V for the LTC1732-4 or below 4.05V for the LTC1732-4.2, a new charge cycle will begin.

The LTC1732 is available in the 10-pin MSOP package.

Float Voltage Recharge Voltage
LTC1732-4 4.1V or 4.2V (pin select) 3.8V
LTC1732-4.2 4.2V 4.05V
LTC1732-8.4 8.4V 8.05V



  • Cellular Phones
  • Handheld Computers
  • Charging Docks and Cradles

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.

PCN-PDN Information

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