LT3844 - High Voltage, Current Mode Switching Regulator Controller with Programmable Operating Frequency

Features

  • High Voltage Operation: Up to 60V
  • Output Voltages up to 36V (Step-Down)
  • Programmable Constant Frequency: 100kHz to 500kHz
  • Synchronizable up to 600kHz
  • Burst Mode® Operation: 120µA Supply Current
  • 10µA Shutdown Supply Current
  • ±1.3% Reference Accuracy
  • Drives N-Channel MOSFET
  • Programmable Soft-Start
  • Programmable Undervoltage Lockout
  • Internal High Voltage Regulator for Gate Drive
  • Thermal Shutdown
  • Current Limit Unaffected by Duty Cycle
  • 16-Pin Thermally Enhanced TSSOP Package
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT3844 Typical Application
LT3844 Typical Application

Description

The LT3844 is a DC/DC controller used for medium power, low part count, high efficiency supplies. It offers a wide 4V-60V input range (7.5V minimum startup voltage) and can implement step-down, step-up, inverting and SEPIC topologies.

The LT3844 includes Burst Mode operation, which reduces quiescent current below 120µA and maintains high efficiency at light loads. An internal high voltage bias regulator allows for simple biasing.

Additional features include current mode control for fast line and load transient response; programmable fixed operating frequency that can be synchronized to an external clock for noise sensitive applications; a gate driver capable of driving large N-channel MOSFETs; a precision undervoltage lockout function; 10µA shutdown current; short-circuit protection and a programmable soft-start function.

The LT3844 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

Part Number Package Code Temp Package
Drawing
RoHS
LT3844EFE#PBF TSSOP-16 FE E 05-08-1663 (BC) Yes
LT3844EFE#TRPBF TSSOP-16 FE E 05-08-1663 (BC) Yes
LT3844IFE#PBF TSSOP-16 FE I 05-08-1663 (BC) Yes
LT3844IFE#TRPBF TSSOP-16 FE I 05-08-1663 (BC) Yes


LT3844 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
(1-99)
Price
(1k)*
RoHS
LT3844EFE#PBF TSSOP-16 E $4.43 $3.10 Yes
LT3844EFE#TRPBF TSSOP-16 E $3.16 Yes
LT3844IFE#PBF TSSOP-16 I $5.50 $3.85 Yes
LT3844IFE#TRPBF TSSOP-16 I $3.91 Yes
Buy NowRequest Samples
* 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
DC974A LT3844EFE Demo Board | 15V ≤ VIN ≤ 60V, Vout = 12V @ 4.2A $150.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT3844IFE#PBF TSSOP-16 I $5.50 $3.85 Yes
LT3844IFE#TRPBF TSSOP-16 I $3.91 Yes
Buy NowRequest Samples
* 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.

Applications

  • Industrial Power Distribution
  • 12V and 42V Automotive and Heavy Equipment
  • High Voltage Single Board Systems
  • Distributed Power Systems
  • Avionics
  • Telecom Power

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Design Tools

LTspice

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 IV:
LT3844

LTpowerCAD

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:
LT3844

Technical Support