ICS557-05A
Quad Differential PCI-Express Clock Source
Description
The ICS557-05A is a spread-spectrum clock generator
that supports PCI-Express requirements. It is used in
PC or embedded systems to substantially reduce
electro-magnetic interference (EMI). The device
provides four differential HCSL or LVDS high-frequency
outputs with spread spectrum capability. The output
frequency and spread type are selectable using
external pins.
Features
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Packaged in 20-pin TSSOP
Available in Pb (lead) free package
Supports PCI-Express applications
Four differential spread spectrum clock outputs
Spread spectrum for EMI reduction
Uses external 25 MHz clock or crystal input
Power down pin turns off chip
OE control tri-states outputs
Spread and frequency selection via external pins
Spread Bypass option available
Industrial temperature range available
Block Diagram
VDD
2
PD
OE
SEL[2:0]
3
Spread
Spectrum/
Output
clock
selection
Spread
Spectrum
Circuitry
CLKOUTA
25 MHz
crystal or
clock
X1
Clock
Oscillator
X2
CLKOUTA
CLKOUTB
PLL Clock
Synthesis
CLKOUTB
CLKOUTC
CLKOUTC
CLKOUTD
CLKOUTD
2
GND
Rr(IREF)
Optional tuning crystal
capacitors
MDS 557-05A E
Integrated Circuit Systems, Inc.
●
1
525 Race Street, San Jose, CA 95126
●
Revision 011606
tel (408) 297-1201
●
www.icst.com
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