LT1937 - White LED Step-Up Converter in SC70 and ThinSOT

Features

  • Click Here For LT1937 Evaluation Kits
  • 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
LT1937
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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.

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Packaging

ThinSOT, SC-70

LT1937
LT1937
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Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT1937ES5 SOT 5 E $1.86   View
LT1937ES5#PBF SOT 5 E $1.86   View
LT1937ES5#TR SOT 5 E $1.86 $1.36 View
LT1937ES5#TRM SOT 5 E $1.86 $1.38 View
LT1937ES5#TRMPBF SOT 5 E $1.86 $1.38 View
LT1937ES5#TRPBF SOT 5 E $1.86 $1.36 View
LT1937ESC6 SC70 6 E $2.14   View
LT1937ESC6#PBF SC70 6 E $2.14   View
LT1937ESC6#TR SC70 6 E $2.14 $1.51 View
LT1937ESC6#TRM SC70 6 E $2.14 $1.53 View
LT1937ESC6#TRMPBF SC70 6 E $2.14 $1.53 View
LT1937ESC6#TRPBF SC70 6 E $2.14 $1.51 View
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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.

Evaluation Kits

Part Number Description Price
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
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Applications

  • Cellular Phones
  • PDAs, Handheld Computers
  • Digital Cameras
  • MP3 Players
  • GPS Receivers
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Simulate

LTSpice / SwitcherCAD III is a powerful FREE circuit simulator and schematic capture program, providing macro models for 80% of Linear Technology's switching regulators, over 200 op amp models, as well as resistors, transistors and MOSFET models.

  • Step 1. If you do not already have a copy of LTSpice, click here to download and install LTSpice / SwitcherCAD III

  • Step 2. Once LTSpice is installed, click here for a ready to run  demonstration circuit of the LT1937.

  • Step 3. If LTspice / SwitcherCAD III does not automatically open after clicking the above link, 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 demonstartion circuit by selecting "Open" from the "File" menu.
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