Power Management Battery Management Battery Charger IC Linear Battery Chargers

LTC1731-4.X - Single Cell Lithium-Ion Linear Battery Charger Controllers

Features

  • Complete Linear Charger Controller for 1-Cell Li-Ion Batteries
  • 1% Voltage Accuracy
  • Programmable Charge Current
  • C/10 Charge Current Detection Output
  • Programmable Charge Termination Timer
  • Space Saving 8-Pin MSOP Package
  • Automatic Sleep Mode When Input Supply is Removed (Only 7µA Battery Drain)
  • Automatic Trickle Charging of Low Voltage Cells
  • Programmable for Constant-Current-Only Mode

Typical Application

LTC1731-4.1 Typical Application

Description

The LTC1731 is a complete constant-current/constant-voltage linear charger controller for single cell lithium-ion batteries. Nickel-cadmium (NiCd) and nickel-metal-hydride (NiMH) batteries can also be charged with constant current using external termination. The external sense resistor sets the charge current with 5% accuracy. An internal resistor divider and precision reference set the final float potential with ±1% accuracy. The output float voltage is set internally to 4.1V (LTC1731-4.1) or 4.2V(LTC1731-4.2).

When the input supply is removed,the LTC1731 automatically enters a low current sleep mode, dropping the battery drain current to typically 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 LTC1731 is available in the 8-pin MSOP and SO packages.

 Float Voltage
LTC1731-4.1 4.1V
LTC1731-4.2 4.2V
LTC1731-8.2 8.2V
LTC1731-8.4 8.4V

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing		 RoHS
LTC1731EMS8-4.1#PBF MS-8 MS8 E 05-08-1660 Yes
LTC1731EMS8-4.1#TRPBF MS-8 MS8 E 05-08-1660 Yes
LTC1731EMS8-4.2#PBF MS-8 MS8 E 05-08-1660 Yes
LTC1731EMS8-4.2#TRPBF MS-8 MS8 E 05-08-1660 Yes
LTC1731ES8-4.1#PBF SO-8 S8 E 05-08-1610 (S8) Yes
LTC1731ES8-4.1#TRPBF SO-8 S8 E 05-08-1610 (S8) Yes
LTC1731ES8-4.2#PBF SO-8 S8 E 05-08-1610 (S8) Yes
LTC1731ES8-4.2#TRPBF SO-8 S8 E 05-08-1610 (S8) Yes


LTC1731-4.1 Package Drawing
LTC1731-4.1 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)		 Price
(1k)*		 RoHS
LTC1731EMS8-4.1#PBF MS-8 E $2.20 $1.75 Yes
LTC1731EMS8-4.1#TRPBF MS-8 E $1.81 Yes
LTC1731EMS8-4.2#PBF MS-8 E $2.20 $1.75 Yes
LTC1731EMS8-4.2#TRPBF MS-8 E $1.81 Yes
LTC1731ES8-4.1#PBF SO-8 E $1.85 $1.55 Yes
LTC1731ES8-4.1#TRPBF SO-8 E $1.61 Yes
LTC1731ES8-4.2#PBF SO-8 E $1.85 $1.55 Yes
LTC1731ES8-4.2#TRPBF SO-8 E $1.61 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • Cellular Phones
  • Handheld Computers
  • Charging Docks and Cradles
  • Programmable Current Source

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