
ICS557-01
PCI-EXPRESS GEN1 CLOCK SOURCE
PCIE
IDT PCI-EXPRESS GEN1 CLOCK SOURCE
2
ICS557-01
REV P 072512
Pin Assignment
Pin Descriptions
1
2
3
X1
4
X2
VD D
IR E F
GN D
CL K
8
7
6
5
OE
8 P i n ( 1 5 0 mi l ) S O I C
Pin
Number
Pin
Name
Pin
Type
Pin Description
1
OE
Input
Output Enable signal
(H = outputs are enabled, L = outputs are disabled/tristated).
Internal pull-up resistor.
2
X1
Input
Crystal or clock input. Connect to a 25 MHz crystal or single ended clock.
3
X2
XO
Crystal Connection. Connect to a parallel mode crystal.
Leave floating if clock input.
4
GND
Power
Connect to ground.
5
IREF
Output
A 475
Ω precision resistor connected between this pin and ground
establishes the external reference current.
6
CLK
Output
HCSL differential complementary clock output.
7
CLK
Output
HCSL differential clock output.
8
VDD
Power
Connect to +3.3 V.