LT3845 - High Voltage Synchronous Current Mode Step-Down Controller with Adjustable Operating Frequency


  • High Voltage Operation: Up to 60V
  • Synchronizable Up to 600kHz
  • Adjustable Constant Frequency: 100kHz to 500kHz
  • Output Voltages Up to 36V
  • Adaptive Nonoverlap Circuitry Prevents Switch Shoot-Through
  • Reverse Inductor Current Inhibit for Discontinuous Operation Improves Efficiency with Light Loads
  • Programmable Soft-Start
  • 120μA No Load Quiescent Current
  • 10μA Shutdown Supply Current
  • 1% Regulation Accuracy
  • Standard Gate N-Channel Power MOSFETs
  • Current Limit Unaffected by Duty Cycle
  • Reverse Overcurrent Protection
  • 16-Lead Thermally Enhanced TSSOP Package, 16-Pin PDIP

Typical Application

LT3845 Typical Application
LT3845 Typical Application


The LT3845 is a high voltage, synchronous, current mode controller used for medium to high power, high efficiency supplies. It offers a wide 4V to 60V input range (7.5V minimum start-up voltage). An onboard regulator simplifies the biasing requirements by providing IC power directly from VIN.

Burst Mode operation maintains high efficiency at light loads by reducing IC quiescent current to 120μA. Light load efficiency is also improved with the reverse inductor current inhibit function which supports discontinuous operation.

Additional features include adjustable fixed operating frequency that can be synchronized to an external clock for noise sensitive applications, gate drivers capable of driving large N-channel MOSFETs, a precision undervoltage lockout, 10μA shutdown current, short-circuit protection and a programmable soft-start.

The LT3845 is available in a 16-lead thermally enhanced TSSOP package and 16-pin through hole N package.

LT3845 -
LT3845A Improved Performance  In Over Current Conditions


For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LT3845EFE#PBF TSSOP-16 FE E 05-08-1663 (BC) RoHS
LT3845EFE#TRPBF TSSOP-16 FE E 05-08-1663 (BC) RoHS
LT3845EN#PBF N-16 N E 05-08-1510 (N16) RoHS
LT3845IFE#PBF TSSOP-16 FE I 05-08-1663 (BC) RoHS
LT3845IFE#TR TSSOP-16 FE I 05-08-1663 (BC) RoHS
LT3845IFE#TRPBF TSSOP-16 FE I 05-08-1663 (BC) RoHS
LT3845MPFE TSSOP-16 FE MP 05-08-1663 (BC) RoHS
LT3845MPFE#PBF TSSOP-16 FE MP 05-08-1663 (BC) RoHS
LT3845MPFE#TR TSSOP-16 FE MP 05-08-1663 (BC) RoHS
LT3845MPFE#TRPBF TSSOP-16 FE MP 05-08-1663 (BC) RoHS

LT3845 Package Drawing
LT3845 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Temp Price
LT3845EFE#PBF TSSOP-16 E $5.09 $3.56 View
LT3845EFE#TRPBF TSSOP-16 E $3.62 View
LT3845EN#PBF N-16 E $5.09 $3.56 View
LT3845IFE#PBF TSSOP-16 I $6.00 $4.20 View
LT3845IFE#TR TSSOP-16 I $4.26 View
LT3845IFE#TRPBF TSSOP-16 I $4.26 View
LT3845MPFE TSSOP-16 MP $15.22 $10.65 View
LT3845MPFE#PBF TSSOP-16 MP $15.22 $10.65 View
LT3845MPFE#TR TSSOP-16 MP $10.71 View
LT3845MPFE#TRPBF TSSOP-16 MP $10.71 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.

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
DC1073A LT3845EFE Demo Board | 20V < Vin < 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


The LTpowerCAD II 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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