LTC4240 - CompactPCI Hot Swap Controller with I²C Compatible Interface


  • Allows Safe Board Insertion and Removal from a Live CompactPCI™ Bus
  • I²C™ Compatible 2-Wire Interface
  • PRECHARGE Output Biases I/O Pins During Card Insertion and Extraction
  • Controls 3.3V, 5V, 12V and –12V Supplies
  • Foldback Current Limit with Circuit Breaker
  • LOCAL_PCI_RST# Logic On-Board
  • QuickSwitch® Enable Output
  • Status LED Driver
  • User Programmable Supply Voltage Power-Up Rate
  • Registers Individual Supply Faults
  • Available in a 28-Pin Narrow SSOP Package

Typical Application

LTC4240 Typical Application


The LTC4240 is a Hot Swap controller that allows a board to be safely inserted and removed from a live CompactPCI bus slot. The LTC4240 has a built-in 2-wire I²C compatible interface to allow software control and monitoring of device function and power supply status. Two external N-channel transistors control the 3.3V and 5V supplies, while two internal switches control the –12V and 12V supplies. Electronic circuit breakers protect all four supplies against overcurrent faults. The PWRGD output indicates when all of the supply voltages are within tolerance. The OFF/ON pin is used to cycle the board power or reset the circuit breaker. The I²C interface allows the user to turn the device off or on, set RESETOUT, turn on the status LED driver and ignore 12V, –12V faults. It also allows the user to read the status of the FAULT, RESETIN, RESETOUT, PWRGD, PRSNT1# and PRSNT2# pins. Under a fault condition, the I²C interface can also be used to determine which of the four supplies generated the fault. The LTC4240 is available in a 28-pin narrow SSOP package.


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
LTC4240CGN#PBF SSOP-28 GN C 05-08-1641 (GN28) Yes
LTC4240CGN#TRPBF SSOP-28 GN C 05-08-1641 (GN28) Yes
LTC4240IGN#PBF SSOP-28 GN I 05-08-1641 (GN28) Yes
LTC4240IGN#TRPBF SSOP-28 GN I 05-08-1641 (GN28) Yes

LTC4240 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
LTC4240CGN#PBF SSOP-28 C $5.25 $4.25 Yes
LTC4240CGN#TRPBF SSOP-28 C $4.65 Yes
LTC4240IGN#PBF SSOP-28 I $6.00 $4.90 Yes
LTC4240IGN#TRPBF SSOP-28 I $5.00 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
DC458A LTC4240CGN | I2C Compact PCI Hot Swap Controller $100.00
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  • Hot Board Insertion into CompactPCI Bus
  • Electronic Circuit Breaker

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