DATASHEET
2 OUTPUT PCI-EXPRESS GEN1 CLOCK SOURCE
ICS557-03
Description
Features
The ICS557-03 is a spread spectrum clock generator that
supports PCI-Express Gen 1 and Ethernet requirements.
The device is used for PC or embedded systems to
substantially reduce electromagnetic interference (EMI).
The device provides two differential (HCSL) spread
spectrum outputs. The spread type and amount are
configured via select pin. Using IDT’s patented
Phase-Locked Loop (PLL) techniques, the device takes a
25 MHz crystal input and produces two pairs of differential
outputs at 25 MHz, 100 MHz, 125 MHz or 200 MHz clock
frequencies for HCSL, and 25 MHz or 100 MHz for LVDS.
• Packaged in 16-pin TSSOP
• RoHS 5 (green) or RoHS 6 (green and lead free)
compliant packaging
• Supports HCSL or LVDS output levels
• Operating voltage of 3.3 V
• Input frequency of 25 MHz
• Jitter 60 ps (cycle-to-cycle)
• Spread Spectrum capability
• Industrial and commercial temperature ranges
• For PCIe Gen2 applications, see the 5V41065
• For PCIe Gen3 applications, see the 5V41235
Block Diagram
VDD
2
SS1:SS0
2
CLK0
CLK0
Control
Logic
S1:S0
2
Phase Lock Loop
CLK1
CLK1
X1/ICLK
Clock
Buffer/
25 MHz
Crystal
crystal or clock
Oscillator
X2
2
GND
Optional tuning crystal
capacitors
Rr(IREF)
OE
IDT® 2 OUTPUT PCI-EXPRESS GEN1 CLOCK SOURCE
1
ICS557-03
REV U 112111