ltc4242cuhf-trpbf Linear Technology Corporation, ltc4242cuhf-trpbf Datasheet - Page 13

• Manufacturer Part Number: ltc4242cuhf-trpbf
• Description: Dual Slot Hot Swap Controller For Pci Express
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
When PRSNT2 pulls low after insertion of a board, the
ENn pin goes low after a delay as determined by the
values of C
and R
Choose C
C
D
D
=
of 47k:
t
DELAY
D
D
to be 33nF.
43 5
and R
1
.
(
ms
D
U
. For plug-in debounce delay of 1ms
)
µF
U
=
0 023
LTC4242
.
CONNECTOR
OUT
Figure 3. RC Network to Generate Delay During Card Plug-In
SYSTEM
BOARD
µF
W
MOTHERBOARD
PRSNT1
V
GND
OUT
GOLD FINGERS
Figure 2. Plug-In Card Insertion/Removal
+
–
SYSTEM BOARD
1.235V
(ACTUAL TRACE ROUTING IS LEFT
U
PCI EXPRESS ADD-IN CARD
UP TO THE BOARD DESIGNER)
TRACE ON THE ADD-IN CARD
9µA
ENn
MATE LAST/BREAK FIRST
PRSNT2
C
33nF
47k
R
D
When the board is removed, the power to the slot is dis-
abled after a delay of:
Turn-On Sequence
The PCI Express power supplies are controlled by the
external N-channel pass transistors, Q1 through Q4, in the
12V and 3.3V power paths, and internal pass transistors
D
BD_PRSNT
t
DELAY
CONNECTOR
2
=
PULL-UP
4242 F02
0 765
.
9
PLUG-IN
HOT PLUG
CONTROL
CARD
LOGIC
C
D
s
4242 F03
LOAD
=
2 8
.
ms
LTC4242
13
4242f