LTC4231 - Micropower Hot Swap Controller


  • Enables Safe Board Insertion and Removal from a Power Supply
  • 4μA Supply Current
  • 0.3μA Shutdown Current
  • Wide Operating Voltage Range: 2.7V to 36V
  • Reverse Supply Protection to –40V
  • Adjustable Analog Current Limit with Circuit Breaker
  • Automatic Retry or Latchoff on Current Fault
  • Overvoltage and Undervoltage Monitoring
  • Controls Single or Back-to-Back N-Channel MOSFETs
  • 12-Lead MSOP and 3mm × 3mm QFN Packages

Typical Application

LTC4231 Typical Application
LTC4231 Typical Application


The LTC®4231 is a micropower Hot Swap™ controller that allows safe circuit board insertion and removal from a live power supply. An internal high side switch driver controls the gate of an external N-channel MOSFET. Back-to-back MOSFETs can be used for reverse supply protection down to –40V.

The LTC4231 provides a debounce delay and allows the GATE to be ramped up at an adjustable rate. After startup, the LTC4231's quiescent current drops to 4μA during normal operation with output active. UVL, UVH, OV and GNDSW monitor overvoltage and undervoltage periodically, keeping total quiescent current low. Pulling SHDN# low shuts down the LTC4231 and quiescent current drops to 0.3μA.

During an overcurrent fault, the LTC4231 actively limits current while running an adjustable timer. The LTC4231-1 remains off after a current fault while the LTC4231-2 automatically reapplies power after a cool-down period.


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
LTC4231CMS-1#PBF MS-12 MS C 05-08-1668 Yes
LTC4231CMS-1#TRPBF MS-12 MS C 05-08-1668 Yes
LTC4231CMS-2#PBF MS-12 MS C 05-08-1668 Yes
LTC4231CMS-2#TRPBF MS-12 MS C 05-08-1668 Yes
LTC4231CUD-1#PBF 3x3 QFN-12 UD C 05-08-1855 Yes
LTC4231CUD-1#TRPBF 3x3 QFN-12 UD C 05-08-1855 Yes
LTC4231CUD-2#PBF 3x3 QFN-12 UD C 05-08-1855 Yes
LTC4231CUD-2#TRPBF 3x3 QFN-12 UD C 05-08-1855 Yes
LTC4231HMS-1#PBF MS-12 MS H 05-08-1668 Yes
LTC4231HMS-1#TRPBF MS-12 MS H 05-08-1668 Yes
LTC4231HMS-2#PBF MS-12 MS H 05-08-1668 Yes
LTC4231HMS-2#TRPBF MS-12 MS H 05-08-1668 Yes
LTC4231HUD-1#PBF 3x3 QFN-12 UD H 05-08-1855 Yes
LTC4231HUD-1#TRPBF 3x3 QFN-12 UD H 05-08-1855 Yes
LTC4231HUD-2#PBF 3x3 QFN-12 UD H 05-08-1855 Yes
LTC4231HUD-2#TRPBF 3x3 QFN-12 UD H 05-08-1855 Yes
LTC4231IMS-1#PBF MS-12 MS I 05-08-1668 Yes
LTC4231IMS-1#TRPBF MS-12 MS I 05-08-1668 Yes
LTC4231IMS-2#PBF MS-12 MS I 05-08-1668 Yes
LTC4231IMS-2#TRPBF MS-12 MS I 05-08-1668 Yes
LTC4231IUD-1#PBF 3x3 QFN-12 UD I 05-08-1855 Yes
LTC4231IUD-1#TRPBF 3x3 QFN-12 UD I 05-08-1855 Yes
LTC4231IUD-2#PBF 3x3 QFN-12 UD I 05-08-1855 Yes
LTC4231IUD-2#TRPBF 3x3 QFN-12 UD I 05-08-1855 Yes

LTC4231 Package Drawing
LTC4231 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
LTC4231CMS-1#PBF MS-12 C $3.21 $2.25 Yes
LTC4231CMS-1#TRPBF MS-12 C $3.27 $2.31 Yes
LTC4231CMS-2#PBF MS-12 C $3.21 $2.25 Yes
LTC4231CMS-2#TRPBF MS-12 C $3.27 $2.31 Yes
LTC4231CUD-1#PBF 3x3 QFN-12 C $3.21 $2.25 Yes
LTC4231CUD-1#TRPBF 3x3 QFN-12 C $3.27 $2.31 Yes
LTC4231CUD-2#PBF 3x3 QFN-12 C $3.21 $2.25 Yes
LTC4231CUD-2#TRPBF 3x3 QFN-12 C $3.27 $2.31 Yes
LTC4231HMS-1#PBF MS-12 H $4.27 $2.99 Yes
LTC4231HMS-1#TRPBF MS-12 H $4.33 $3.05 Yes
LTC4231HMS-2#PBF MS-12 H $4.27 $2.99 Yes
LTC4231HMS-2#TRPBF MS-12 H $4.33 $3.05 Yes
LTC4231HUD-1#PBF 3x3 QFN-12 H $4.27 $2.99 Yes
LTC4231HUD-1#TRPBF 3x3 QFN-12 H $4.33 $3.05 Yes
LTC4231HUD-2#PBF 3x3 QFN-12 H $4.27 $2.99 Yes
LTC4231HUD-2#TRPBF 3x3 QFN-12 H $4.33 $3.05 Yes
LTC4231IMS-1#PBF MS-12 I $3.71 $2.60 Yes
LTC4231IMS-1#TRPBF MS-12 I $3.77 $2.66 Yes
LTC4231IMS-2#PBF MS-12 I $3.71 $2.60 Yes
LTC4231IMS-2#TRPBF MS-12 I $3.77 $2.66 Yes
LTC4231IUD-1#PBF 3x3 QFN-12 I $3.71 $2.60 Yes
LTC4231IUD-1#TRPBF 3x3 QFN-12 I $3.77 $2.66 Yes
LTC4231IUD-2#PBF 3x3 QFN-12 I $3.71 $2.60 Yes
LTC4231IUD-2#TRPBF 3x3 QFN-12 I $3.77 $2.66 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.

Part Number Description Price Documentation
DC2161A-A LTC4231IMS-1 Demo Board | Micropower Hot Swap Controller with Latch-Off $75.00
DC2161A-B LTC4231IMS-2 Demo Board | Micropower Hot Swap Controller with Auto-Retry $75.00
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Click here to view our complete list of demo boards


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