Features and Benefits

  • Allows Safe Board Insertion and Removal from a Live Backplane
  • Controls Supply Voltage from 10.8V to 80V
  • Foldback Current Limiting
  • Overcurrent Fault Detection
  • Drives an External N-Channel MOSFET
  • Programmable Supply Voltage Power-Up Rate
  • Undervoltage Protection
  • Latch Off Operation Mode (LT4256-1)
  • Automatic Retry (LT4256-2)
  • Available in an 8-Pin SO Package

Product Details

The LT4256-1/LT4256-2 are high voltage Hot Swap controllers that allow a board to be safely inserted and removed from a live backplane. An internal driver drives an external N-channel MOSFET switch to control supply voltages ranging from 10.8V to 80V.

The LT4256-1/LT4256-2 features an adjustable analog foldback current limit. If the supply remains in current limit for more than a programmable time, the N-channel MOSFET shuts off and the PWRGD output asserts low. The LT4256-2 automatically restarts after a time-out delay. The LT4256-1 latches off until the UV pin is cycled low.

The PWRGD output indicates when the output voltage rises above a programmed level. An external resistor string from VCC provides programmable undervoltage protection.

The LT4256 can be used as an upgrade to LT1641 designs.

The LT4256-1 and LT4256-2 are available in an 8-pin SO package that is pin compatible with the LT1641.

Retry / Latch Off Features Package
LT4256-1 Latch Off UV SO-8
LT4256-2 Retry UV SO-8
LT4256-3 Latch Off or Retry UV/OV, Open Circuit Detect SSOP-16


  • Hot Board Insertion
  • Electronic Circuit Breaker/Power Bussing
  • Industrial High Side Switch/Circuit Breaker
  • 24V/48V Industrial/Alarm Systems
  • Ideally Suited for 12V, 24V and 48V Distributed Power Systems
  • 48V Telecom Systems

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (3)

Tools & Simulations


LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, 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.


Models for the following parts are available in LTspice:


Product Recommendations

LT4256-1 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

PCN-PDN Information

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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.