LT3845A - High Voltage Synchronous Current Mode Step-Down Controller with Adjustable Operating Frequency

Features

  • High Voltage Operation: Up to 60V
  • Synchronizable Up to 600kHz
  • Adjustable Constant Frequency: 100kHz to 500kHz
  • Output Voltages Up to 36V
  • Stable Operation in Current Limit
  • 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
  • Reverse Overcurrent Protection
  • 16-Lead Thermally Enhanced TSSOP Package

Typical Application

LT3845A Typical Application
LT3845A Typical Application

Description

The LT3845A 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 LT3845A is available in a 16-lead thermally enhanced TSSOP package.

Packaging

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

TSSOP-16

LT3845A Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT3845AEFE#PBF TSSOP 16 E $5.09 $3.56 View
LT3845AEFE#TRPBF TSSOP 16 E $3.62 View
LT3845AIFE#PBF TSSOP 16 I $5.89 $4.12 View
LT3845AIFE#TRPBF TSSOP 16 I $4.18 View
LT3845AMPFE#PBF TSSOP 16 MP $15.22 $10.65 View
LT3845AMPFE#TRPBF TSSOP 16 MP $10.71 View
LT3845EFE#PBF TSSOP 16 E $5.09 $3.56 View
LT3845EFE#TRPBF TSSOP 16 E $3.62 View
LT3845EN#PBF PDIP 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
DC1619A LT3845AEFE Demo Board | 16V ≤ VIN ≤ 60V, VOUT = 12V @ 10A. $150.00
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Click here to view our complete list of demo boards

Applications

  • 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

LTpowerCAD

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:
LT3845

LTspiceIV

LTspice IV 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 IV

To launch a ready to run LTspice demonstration circuit for this part:

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice IV:
LT3845
LT3845A

Technical Support