1. Products
  2. Power Monitor, Control, and Protection
  3. Hot Swap Controllers
  4. Low Voltage Hot Swap Controllers
  5. LT4239


Features and Benefits

  • Allows Safe Board Insertion into Live Backplane
  • Wide Operating Voltage Range: 4V to 20V
  • Dual Gate Drivers for High Current Applications
  • Withstands Surge Voltage without Protection TVS
  • Monitors VGS and VDS for MOSFET Health
  • Accurate 10mV ± 5% Circuit Breaker Threshold
  • Boost Mode for Load Surges
  • Current Monitor Output
  • 12V Gate Drive for Lower MOSFET RDS(ON)
  • Adjustable Start-Up and Overcurrent Fault Delay
  • Input Undervoltage Protection
  • Fault and Power Good Output
  • 16-Lead 4mm × 3mm DFN Package

Product Details

The LT4239 hot swap controller allows a board to be safely inserted and removed from a live backplane. Using external N-channel pass transistors, board supply voltage and inrush current are ramped up at a controlled rate. Dual 12V gate drive supports high current loads by providing a two-stage start-up that first charges the load capacitance followed by enabling a low on-resistance path to the load. The supply output is protected against short-circuit faults with a fast-acting electronic circuit breaker.

By placing the sense resistor on the output side and an RC filter at the device’s supply pin, the MOSFET avalanching can suppress the surge voltage when it is abruptly turned off without the additional TVS at the board supply input.

The LT4239 features a current monitor that amplifies the voltage across an external sense resistor. It also provides undervoltage protection, and reports fault and power good status for the supply. A boost mode allows the circuit breaker and current limit thresholds to be raised to ride through load surges without generating a fault.


  • Electronic Circuit Breaker
  • Enterprise Servers and Data Storage Systems
  • Network Routers and Switches

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.

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.


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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.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
LT4239ADE#PBF Material Declaration Reliability Data 16-Lead DFN (4mm x 3mm w/ EP)
Wafer Fabrication Data

Sample & Buy

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Buy Now Pricing

(**) Displayed Buy Now Price and Price Range is based on small quantity orders.


List Pricing

(*)The 1Ku 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 Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

Please see the latest communication from our CCO regarding lead times.



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