LT1937 - White LED Step-Up Converter in SC70 and ThinSOT
Features
- Inherently Matched LED Current
- High Efficiency: 84% Typical
- Drives Up to Four LEDs from a 3.2V Supply
- Drives Up to Six LEDs from a 5V Supply
- 36V Rugged Bipolar Switch
- Fast 1.2MHz Switching Frequency
- Uses Tiny 1mm Tall Inductors
- Requires Only 0.22µF Output Capacitor
- Low Profile SC70 and ThinSOT™ Packaging
Typical Application
Description
The LT1937 is a step-up DC/DC converter specifically designed to drive white LEDs with a constant current. The device can drive two, three or four LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The LT1937 switches at 1.2MHz, allowing the use of tiny external components. The output capacitor can be as small as 0.22µF, saving space and cost versus alternative solutions. A low 95mV feedback voltage minimizes power loss in the current setting resistor for better efficiency.
The LT1937 is available in low profile SC70 and ThinSOT packages.
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 |
|---|---|---|---|---|---|
| LT1937ES5#PBF | SOT-23 | S5 | E | 05-08-1635 | Yes |
| LT1937ES5#TRMPBF | SOT-23 | S5 | E | 05-08-1635 | Yes |
| LT1937ES5#TRPBF | SOT-23 | S5 | E | 05-08-1635 | Yes |
| LT1937ESC6#PBF | SC-70 | SC6 | E | 05-08-1638 | Yes |
| LT1937ESC6#TRMPBF | SC-70 | SC6 | E | 05-08-1638 | Yes |
| LT1937ESC6#TRPBF | SC-70 | SC6 | E | 05-08-1638 | Yes |
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 | |
|---|---|---|---|---|---|---|
| LT1937ES5#PBF | SOT-23 | E | $1.86 | Yes | ||
| LT1937ES5#TRMPBF | SOT-23 | E | $1.86 | $1.38 | Yes | |
| LT1937ES5#TRPBF | SOT-23 | E | $1.86 | $1.36 | Yes | |
| LT1937ESC6#PBF | SC-70 | E | $2.14 | Yes | ||
| LT1937ESC6#TRMPBF | SC-70 | E | $2.14 | $1.53 | Yes | |
| LT1937ESC6#TRPBF | SC-70 | E | $2.14 | $1.51 | Yes | |
| Buy Now • Request Samples | ||||||
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.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC484A | LT1937ES5 | Single Cell White LED(4) Driver with On-Board Battery, Vin 2.7V - 5V | $75.00 | |
| DC507A | LT1937ESC6 | 2-Ckt, High Efficiency Constant-Current Single Cell Li-Ion White LED (4) Driver with On-Board Battery | $75.00 | |
| Buy Now | |||
Applications
- Cellular Phones
- PDAs, Handheld Computers
- Digital Cameras
- MP3 Players
- GPS Receivers
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
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Models for the following parts are available in LTspice:
LT1937
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.
