LT3800 - High-Voltage Synchronous Current Mode Step-Down Controller


  • Wide 4V to 60V Input Voltage Range
  • Output Voltages up to 36V
  • Adaptive Nonoverlap Circuitry Prevents Switch Shoot-Through
  • Reverse Inductor Current Inhibit for Discontinuous Operation Improves Efficiency with Light Loads
  • Output Slew Rate Controlled Soft-Start with Auto-Reset
  • 100µA No Load Quiescent Current
  • Low 10µA Current Shutdown
  • 1% Regulation Accuracy
  • 200kHz Operating Frequency
  • Standard Gate N-Channel Power MOSFETs
  • Current Limit Unaffected by Duty Cycle
  • Reverse Overcurrent Protection
  • 16-Lead Thermally Enhanced TSSOP Package

Typical Application

LT3800 Typical Application
LT3800 Typical Application


The LT3800 is a 200kHz fixed frequency high voltage synchronous current mode step-down switching regulator controller. The IC drives standard gate N-channel power MOSFETs and can operate with input voltages from 4V to 60V. An onboard regulator provides IC power directly from VIN and provides for output-derived power to minimize VIN quiescent current. MOSFET drivers employ an internal dynamic bootstrap feature, maximizing gate-source "ON" voltages during normal operation for improved operating efficiencies. The LT3800 incorporates Burst Mode operation, which reduces no load quiescent current to under 100µA. Light load efficiencies are also improved through a reverse inductor current inhibit, allowing the controller to support discontinuous operation. Both Burst Mode operation and the reverse-current inhibit features can be disabled if desired. The LT3800 incorporates a programmable soft-start that directly controls the voltage slew rate of the converter output for reduced startup surge currents and overshoot errors. The LT3800 is available in a 16-lead thermally enhanced TSSOP package.

Protected by U.S. Patents, including 5481178, 6611131, 6304066, 6498466, 6580258.


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
LT3800EFE#PBF TSSOP-16 FE E 05-08-1663 (BC) Yes
LT3800EFE#TRPBF TSSOP-16 FE E 05-08-1663 (BC) Yes
LT3800IFE#PBF TSSOP-16 FE I 05-08-1663 (BC) Yes
LT3800IFE#TRPBF TSSOP-16 FE I 05-08-1663 (BC) Yes

LT3800 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
LT3800EFE#PBF TSSOP-16 E $3.69 $3.10 Yes
LT3800EFE#TRPBF TSSOP-16 E $3.20 Yes
LT3800IFE#PBF TSSOP-16 I $5.64 $3.95 Yes
LT3800IFE#TRPBF TSSOP-16 I $4.07 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
DC720A LT3800EFE Demo Board | Vin = 20V to 55V, Vout = 12V @ 6.25A $150.00
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Click here to view our complete list of demo boards


  • 12V and 42V Automotive and Heavy Equipment
  • 48V Telecom Power Supplies
  • Avionics and Industrial Control Systems
  • Distributed Power Converters

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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
  • 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:


The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:

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