Monitor, Control and Protection Hot Swap Controllers High Voltage Hot Swap Controllers

LTC4251B - Negative Voltage Hot Swap Controllers in SOT-23

Features

  • Allows Safe Board Insertion and Removal from a Live –48V Backplane
  • Floating Topology Permits Very High Voltage Operation
  • Programmable Analog Current Limit with Circuit Breaker Timer
  • Fast Response Time Limits Peak Fault Current
  • Improved Ruggedness Shunt Regulator
  • Programmable Timer
  • Programmable Undervoltage/Overvoltage Protection
  • Low Profile 6-Lead SOT-23 (ThinSOT™) Package

Typical Application

LTC4251B Typical Application
LTC4251B Typical Application

Description

The LTC®4251B/LTC4251B-1/LTC4251B-2 negative voltage Hot Swap™ controllers allow 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.

Programmable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The supply input is shunt regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial start-up and controls the circuit breaker’s response time.

The LTC4251B UV/OV thresholds are designed to match the standard telecom operating range of – 43V to –75V. The LTC4251B-1 UV/OV thresholds extend the operating range to encompass –36V to –72V. The LTC4251B-2 implements a UV threshold of –43V only. The LTC4251B improves the ruggedness of the LTC4251 shunt regulator.

  UV/OV
LTC4251 -43V / -75V
LTC4251-1 -36V / -72V
LTC4251-2 -43V UV Only
LTC4251B -43V / -75V
LTC4251B-1 -36V / -72V
LTC4251B-2 -43V UV Only

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
LTC4251BCS6-1#PBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6-1#TRMPBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6-1#TRPBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6-2#PBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6-2#TRMPBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6-2#TRPBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6#PBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6#TRMPBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BCS6#TRPBF SOT-23 S6 C 05-08-1636 Yes
LTC4251BIS6-1#PBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6-1#TRMPBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6-1#TRPBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6-2#PBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6-2#TRMPBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6-2#TRPBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6#PBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6#TRMPBF SOT-23 S6 I 05-08-1636 Yes
LTC4251BIS6#TRPBF SOT-23 S6 I 05-08-1636 Yes


LTC4251B 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
LTC4251BCS6-1#PBF SOT-23 C $2.36 Yes
LTC4251BCS6-1#TRMPBF SOT-23 C $2.36 $2.06 Yes
LTC4251BCS6-1#TRPBF SOT-23 C $2.36 $2.01 Yes
LTC4251BCS6-2#PBF SOT-23 C $2.36 Yes
LTC4251BCS6-2#TRMPBF SOT-23 C $2.36 $2.06 Yes
LTC4251BCS6-2#TRPBF SOT-23 C $2.36 $2.01 Yes
LTC4251BCS6#PBF SOT-23 C $2.36 Yes
LTC4251BCS6#TRMPBF SOT-23 C $2.36 $2.06 Yes
LTC4251BCS6#TRPBF SOT-23 C $2.36 $2.01 Yes
LTC4251BIS6-1#PBF SOT-23 I $2.66 Yes
LTC4251BIS6-1#TRMPBF SOT-23 I $2.66 $2.31 Yes
LTC4251BIS6-1#TRPBF SOT-23 I $2.66 $2.26 Yes
LTC4251BIS6-2#PBF SOT-23 I $2.66 Yes
LTC4251BIS6-2#TRMPBF SOT-23 I $2.66 $2.31 Yes
LTC4251BIS6-2#TRPBF SOT-23 I $2.66 $2.26 Yes
LTC4251BIS6#PBF SOT-23 I $2.66 Yes
LTC4251BIS6#TRMPBF SOT-23 I $2.66 $2.31 Yes
LTC4251BIS6#TRPBF SOT-23 I $2.66 $2.26 Yes
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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 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

Applications

  • Hot Board Insertion
  • Electronic Circuit Breaker
  • –48V Distributed Power Systems
  • Negative Power Supply Control
  • Central Office Switching
  • Programmable Current Limiting Circuit
  • High Availability Servers
  • Disk Arrays

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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:
LTC4251
LTC4251-1
LTC4251-2

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