LTC4242 Datasheet, PDF (1/24 Pages) Linear Technology – Dual Slot Hot Swap Controller for PCI Express

LTC4242
Dual Slot Hot Swap
Controller for PCI Express
FEATURES
■ _{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
U
APPLICATIO S
■ _{PCI Express-Based PC and Servers}
■ _{Hot Swap Application for Triple Supply Systems}
DESCRIPTIO
The LTC^®4242 Hot Swap^TM 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 V_CC 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.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
PCI Express Application
12V
12V_OUT
3.3V
3.3V_OUT
3.3V
PCI EXPRESS
HOT PLUG
CONTROLLER
3.3V
12V_IN1 12V_SENSE1 12V_GATE1 12V_OUT1 3V_IN1
V_CC
3V_SENSE1 3V_GATE1
3V_OUT1
AUXOUT1
AUXIN1
AUXON1
ON1
FAULT1
AUXFAULT1
PGOOD1
PGOOD2
AUXFAULT2
FAULT2
ON2
AUXON2
LTC4242G
AUXIN2
12V_IN2 12V_SENSE2 12V_GATE2 12V_OUT2 3V_IN2
FON1
EN1
GND
EN2
FON2
AUXOUT2
3V_OUT2
3V_SENSE2 3V_GATE2
BD_PRST1
3.3V_OUT
PCIe PLUG-IN
CONNECTOR CARD
BD_PRST2
3.3V_OUT
ENn
5V/DIV
AUXOUTn
5V/DIV
12V_OUTn
5V/DIV
3V_OUTn
5V/DIV
PGOODn
5V/DIV
3.3V
12V
3.3V_OUT
12V_OUT
4242 TA01a
PCIe PLUG-IN
CONNECTOR CARD
Normal Power-Up Sequence
10ms/DIV
4242 F04
4242f
1