LTC1731-8.4 and 8.2 - Lithium-Ion Linear Battery Charger Controller
Features
- Complete Linear Charger Controller for 2-Cell Lithium-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 (15µA Battery Drain)
- Automatic Trickle Charging of Low Voltage Cells
- Programmable for Constant-Current-Only Mode
Typical Application
Description
The LTC1731-8.2/LTC1731-8.4 are complete constant-current/constant-voltage linear charger controllers for 2-cell lithium-ion (Li-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 7% accuracy. An internal resistor divider and precision reference set the final float potential with 1% accuracy. The output float voltages are set internally to 8.2V (LTC1731-8.2) or 8.4V (LTC1731-8.4).
When the input supply is removed, the LTC1731-8.2/LTC1731-8.4 automatically enter a low current sleep mode, dropping the battery drain current to typically 15µA. 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 battery voltage exceeds 4.95V.
The LTC1731-8.2/LTC1731-8.4 are available in the 8-pin MSOP and SO packages. For 1-cell Li-Ion battery charging, see the LTC1731-4.1 and LTC1731-4.2 data sheets.
Packaging
For complete and up to date package information and drawings, please refer to our packaging page
MS-8, SO-8
Order Info
- Part numbers ending in PBF are lead free. Please contact LTC marketing for information on lead based finish parts.
- 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 | Pins | Temp | Price (1-99) | Price (1k)* | RoHS Data |
|---|---|---|---|---|---|---|
| LTC1731EMS8-4.1 | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-4.1#PBF | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-4.1#TR | MSOP | 8 | E | $1.81 | View | |
| LTC1731EMS8-4.1#TRPBF | MSOP | 8 | E | $1.81 | View | |
| LTC1731EMS8-4.2 | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-4.2#PBF | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-4.2#TR | MSOP | 8 | E | $1.81 | View | |
| LTC1731EMS8-4.2#TRPBF | MSOP | 8 | E | $1.81 | View | |
| LTC1731EMS8-8.2 | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-8.2#PBF | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-8.2#TR | MSOP | 8 | E | $1.81 | View | |
| LTC1731EMS8-8.2#TRPBF | MSOP | 8 | E | $1.81 | View | |
| LTC1731EMS8-8.4 | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-8.4#PBF | MSOP | 8 | E | $2.20 | $1.75 | View |
| LTC1731EMS8-8.4#TR | MSOP | 8 | E | $1.81 | View | |
| LTC1731EMS8-8.4#TRPBF | MSOP | 8 | E | $1.81 | View | |
| LTC1731ES8-4.1 | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-4.1#PBF | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-4.1#TR | SO | 8 | E | $1.61 | View | |
| LTC1731ES8-4.1#TRPBF | SO | 8 | E | $1.61 | View | |
| LTC1731ES8-4.2 | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-4.2#PBF | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-4.2#TR | SO | 8 | E | $1.61 | View | |
| LTC1731ES8-4.2#TRPBF | SO | 8 | E | $1.61 | View | |
| LTC1731ES8-8.2 | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-8.2#PBF | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-8.2#TR | SO | 8 | E | $1.61 | View | |
| LTC1731ES8-8.2#TRPBF | SO | 8 | E | $1.61 | View | |
| LTC1731ES8-8.4 | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-8.4#PBF | SO | 8 | E | $1.85 | $1.55 | View |
| LTC1731ES8-8.4#TR | SO | 8 | E | $1.61 | View | |
| LTC1731ES8-8.4#TRPBF | SO | 8 | E | $1.61 | View | |
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Applications
- Cellular Phones
- Handheld Computers
- Charging Docks and Cradles
- Programmable Current Source
Simulate
LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.