LT3433 - High Voltage Step-Up/Step-Down DC/DC Converter


  • Automatic Step-Up and Step-Down Conversion
  • Uses a Single Inductor
  • Wide 4V to 60V Input Voltage Range
  • VOUT from 3.3V to 20V
  • Dual Internal 500mA Switches
  • 100µA No-Load Quiescent Current
  • Low Current Shutdown
  • ±1% Output Voltage Accuracy
  • 200kHz Operating Frequency
  • Boosted Supply Pin to Saturate High Side Switch
  • Frequency Foldback Protection
  • Current Limit Foldback Protection
  • Current Limit Unaffected by Duty Cycle
  • 16-lead Thermally Enhanced TSSOP Package

Typical Application

LT3433 Typical Application
LT3433 Typical Application
LT3433 Typical Application


The LT3433 is a 200kHz fixed-frequency current mode switching regulator that provides both step-up and stepdown regulation using a single inductor. The IC operates over a 4V to 60V input voltage range making it suitable for use in various wide input voltage range applications such as automotive electronics that must withstand both load dump and cold crank conditions.

Internal control circuitry monitors system conditions and converts from single switch buck operation to dual switch bridged operation when required, seamlessly changing between step-down and step-up voltage conversion.

Optional Burst Mode operation reduces no-load quiescent current to 100µA and maintains high efficiencies with light loads.

Current limit foldback and frequency foldback help prevent inductor current runaway during start-up. Programmable soft-start helps prevent output overshoot at start-up.

The LT3433 is available in a 16-lead thermally enhanced TSSOP 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
LT3433EFE#PBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT3433EFE#TRPBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT3433IFE#PBF TSSOP-16 FE I 05-08-1663 (BB) Yes
LT3433IFE#TRPBF TSSOP-16 FE I 05-08-1663 (BB) Yes

LT3433 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
LT3433EFE#PBF TSSOP-16 E $4.64 $3.25 Yes
LT3433EFE#TRPBF TSSOP-16 E $3.37 Yes
LT3433IFE#PBF TSSOP-16 I $5.36 $3.75 Yes
LT3433IFE#TRPBF TSSOP-16 I $3.87 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
DC527A LT3433EFE | Step-Up/Step-Down Converter, 4V to 60V Input, Vout=5V/400mA @ 12Vin, See Load Current Table $125.00
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Click here to view our complete list of demo boards


  • 12V Automotive Systems
  • Wall Adapter Powered Systems
  • Battery Power Voltage Buffering

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Design Tools


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
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