LT1942 - Quad DC/DC Converter for Triple Output TFT Supply Plus LED Driver


  • Triple Output TFT Supply with Built-In Power Sequencing
  • Integrated White LED Backlight Driver
  • Integrated Schottky Diodes
  • Active Ballast Circuitry Ensures Precise Current Matching in White LEDs
  • Low Noise 1MHz Fixed Frequency Operation
  • 2.6V to 16V Input Voltage Range
  • Soft-Start Limits Inrush Current
  • TFT Supply Output Voltages Independently Set (Not Charge Pump Derived)
  • Power Good and Output Disconnect for TFT Supply
  • Built-In LED Dimming Capability
  • Open LED Protection for LED Driver
  • 24-Lead QFN Package (4mm × 4mm)

Typical Application

LT1942 Typical Application


The LT1942 is a highly integrated quad switching regulator designed to provide all necessary power supply functions for TFT displays, including the white LED backlight driver. The TFT supply incorporates two boost and one inverting DC/DC converters. The TFT supply output voltages are independently set, unlike charge pump solutions which have many limitations. Power sequencing for the TFT supply is built into the part and is user programmable.

The LED driver is a boost DC/DC converter that can be independently controlled. The LED driver has built-in dimming control for precise control of LED current. An 8:1 dimming range is achieved by adjusting the CTRL4 voltage.The user can elect to drive a single string or two strings of LEDs. An LED ballast circuit is included to precisely match the LED currents if two strings of LEDs are used. Soft-start is built into the LED driver as well as the primary TFT supply.

The LT1942 is available in a low profile (0.75mm) 24-lead QFN (4mm × 4mm) package.


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
LT1942EUF#PBF 4x4 QFN-24 UF E 05-08-1697 Yes
LT1942EUF#TRPBF 4x4 QFN-24 UF E 05-08-1697 Yes

LT1942 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
LT1942EUF#PBF 4x4 QFN-24 E $3.27 $2.75 Yes
LT1942EUF#TRPBF 4x4 QFN-24 E $2.85 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
DC688A LT1942EUF | Quad Converter For TFT Supply and LED Driver, Vin=3V-4.5V, Von=10V/2mA, Voff=-10V/2mA, AVdd=5V/40mA $100.00
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Click here to view our complete list of demo boards


  • Poly-Silicon TFT Displays
  • Amorphous Silicon TFT Displays

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

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