Overview

Features and Benefits

  • Allows Safe Board Insertion and Removal from a Live –48V Backplane
  • Floating Topology Permits Very High Voltage Operation
  • Current Limit With Circuit Breaker Timer
  • Fast Response Time Limits Peak Fault Current
  • Programmable Soft-Start Current Limit
  • Programmable Timer with Drain Voltage Accelerated Response
  • ±1% Undervoltage/Overvoltage Threshold Accuracy (LTC4252A)
  • Adjustable Undervoltage/Overvoltage Protection
  • LTC4252-1/LTC4252A-1: Latch Off After Fault
  • LTC4252-2/LTC4252A-2: Automatic Retry After Fault
  • Available in 8-Pin and 10-Pin MSOP Packages

Product Details

The LTC4252 negative voltage Hot Swap™ controller allows a board to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current limiting: a timed circuit breaker, active current limiting and a fast feedforward path that limits peak current under worst-case catastrophic fault conditions.

Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4252’s supply input is shunt regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial startup and controls the circuit breaker’s response time. The circuit breaker’s response time is accelerated by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable softstart circuit controls MOSFET inrush current at start-up.

The LTC4252-1/LTC4252A-1 latch off after a circuit breaker fault times out. The LTC4252-2/LTC4252A-2 provide automatic retry after a fault. The LTC4252A-1/LTC4252A-2 feature tight ±1% undervoltage/overvoltage threshold accuracy. The LTC4252 is available in either an 8-pin or 10-pin MSOP, while the LTC4252A is available in the 10-pin MSOP.

UV/OV % Latch Off/Retry Package
LTC4252-1 4.6% Latch off MS-8, MS-10
LTC4252-2 4.8% Retry MS-8, MS-10
LTC4252A-1 1% Latch off MS-10
LTC4252A-2 1% Retry MS-10
LTC4252B-1 4.6% Latch off MS-8, MS-10
LTC4252B-2 4.6% Retry MS-8, MS-10
LTC4252C-1 1% Latch off MS-10
LTC4252C-2 1% Retry MS-10

Applications

  • Hot Board Insertion
  • Electronic Circuit Breaker
  • –48V Distributed Power Systems
  • Negative Power Supply Control
  • Central Office Switching
  • High Availability Servers
  • ATCA

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Tools & Simulations

LTspice

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.

LTspice

Models for the following parts are available in LTspice:

LTC4252C-1
LTC4252C-2

Product Recommendations

LTC4252-1 Companion Parts

Recommended Related Parts

Reference Materials

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.

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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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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