LTC4242 - Dual Slot Hot Swap Controller for PCI Express


  • Allows Live Insertion into PCI Express® Backplane
  • Controls Two Independent PCI Express Slots
  • Independent Control of Main and Auxiliary Supplies
  • 20V Rating for 12V Supply Input Pins
  • Integrated 0.25Ω AUX Switches
  • Limits Fault Current in ≤1µs
  • Force On Test Mode
  • Adjustable Supply Voltage Power-Up Rate
  • High Side Drivers for N-Channel MOSFETs
  • Thermal Shutdown Protection
  • Available in 38-Lead QFN and 36-Lead SSOP Packages

Typical Application

LTC4242 Typical Application
LTC4242 Typical Application


The LTC4242 Hot SwapTM controller allows safe board insertion and removal for two independent slots on a PCI Express backplane. External N-channel transistors control the 12V and 3.3V supplies while integrated switches control the 3.3V auxiliary supplies. Both 12V and 3.3V supplies can be ramped up at an adjustable rate. Dual level circuit breakers and fast active current limiting protect all supplies against overcurrent faults.

A supply filter at the VCC pin allows the LTC4242 to endure supply transients. The EN input detects the presence of a card in the PCI Express slot. The FAULT and AUXFAULT outputs alert the system of overcurrent conditions on the main and auxiliary supplies, respectively. PGOOD and AUXPGOOD outputs indicate proper main and auxiliary supply outputs.


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
LTC4242CG#PBF SSOP-36 G C 05-08-1640 (G36) Yes
LTC4242CG#TRPBF SSOP-36 G C 05-08-1640 (G36) Yes
LTC4242CUHF#PBF 5x7 QFN-38 UHF C 05-08-1701 Yes
LTC4242CUHF#TRPBF 5x7 QFN-38 UHF C 05-08-1701 Yes
LTC4242IG#PBF SSOP-36 G I 05-08-1640 (G36) Yes
LTC4242IG#TRPBF SSOP-36 G I 05-08-1640 (G36) Yes
LTC4242IUHF#PBF 5x7 QFN-38 UHF I 05-08-1701 Yes
LTC4242IUHF#TRPBF 5x7 QFN-38 UHF I 05-08-1701 Yes

LTC4242 Package Drawing
LTC4242 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
LTC4242CG#PBF SSOP-36 C $4.71 $3.30 Yes
LTC4242CG#TRPBF SSOP-36 C $3.36 Yes
LTC4242CUHF#PBF 5x7 QFN-38 C $4.71 $3.30 Yes
LTC4242CUHF#TRPBF 5x7 QFN-38 C $3.36 Yes
LTC4242IG#PBF SSOP-36 I $5.64 $3.96 Yes
LTC4242IG#TRPBF SSOP-36 I $4.02 Yes
LTC4242IUHF#PBF 5x7 QFN-38 I $5.64 $3.96 Yes
LTC4242IUHF#TRPBF 5x7 QFN-38 I $4.02 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
DC1054A/B DC1054A with DC1054B | LTC4242 Dual PCI Express Hot Swap Controller $75.00
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  • PCI Express-Based PC and Servers
  • Hot Swap Application for Triple Supply Systems

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