LT4351 - MOSFET Diode-OR Controller

Features

  • Low Loss Replacement for ORing Diode in Multiple Sourced Power Supplies
  • External N-Channel MOSFETs for High Current Capability
  • Internal Boost Regulator Supply for MOSFET Gate Drive
  • Wide Input Range: 1.2V to 18V
  • Fast Switching MOSFET Gate Control
  • Input Under and Overvoltage Detection
  • STATUS and FAULT Outputs for Monitoring
  • Internal MOSFET Gate Clamp
  • Available in a 10-pin MSOP
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT4351 Typical Application

Description

The LT4351 creates a near-ideal diode using external single or back-to-back N-channel MOSFETs. This ideal diode function permits low loss ORing of multiple power sources. Power sources can easily be ORed together to increase total system power and reliability with minimal effect on supply voltage or efficiency. Disparate power supplies can be efficiently ORed together.

The IC monitors the input supply with respect to the load and turns on the MOSFET(s) when the input supply is higher. If the MOSFET’s RDS(ON) is sufficiently small, the LT4351 will regulate the voltage across the MOSFET(s) to 15mV. A STATUS pin indicates the MOSFET on state.

An internal boost regulator generates the MOSFET gate drive voltage. Low operating voltage allows for OR’ing of supplies as low as 1.2V.

The LT4351 will disable power passage during undervoltage or overvoltage conditions. These voltages are set by resistive dividers on the UV and OV pins. The undervoltage threshold has user programmable hysteresis. Overvoltage detection is filtered to reduce false triggering.

The LT4351 is available in a 10-pin MSOP.

Packaging

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
Drawing
RoHS
LT4351CMS#PBF MS-10 MS C 05-08-1661 Yes
LT4351CMS#TRPBF MS-10 MS C 05-08-1661 Yes
LT4351IMS#PBF MS-10 MS I 05-08-1661 Yes
LT4351IMS#TRPBF MS-10 MS I 05-08-1661 Yes


LT4351 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
LT4351CMS#PBF MS-10 C $2.90 $2.50 Yes
LT4351CMS#TRPBF MS-10 C $2.56 Yes
LT4351IMS#PBF MS-10 I $3.35 $2.90 Yes
LT4351IMS#TRPBF MS-10 I $2.96 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.

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
LT4351IMS#PBF MS-10 I $3.35 $2.90 Yes
LT4351IMS#TRPBF MS-10 I $2.96 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

  • Paralleled Power Supplies
  • Uninterrupted Supplies
  • High Availability Systems
  • N + 1 Redundant Power Supplies

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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

Models for the following parts are available in LTspice:
LT4351

Technical Support