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

LT1937 Typical Application
LT1937 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


LT1937 Package Drawing
LT1937 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
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
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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.

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
Click here to view our complete list of demo boards

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

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LT1937

Technical Support