ICS557-05A

www.DataSheet4U.com 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 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 ICS557-05A Quad Differential PCI-Express Clock Source Pin Assignment VDDXD S0 S1 S2 X1 X2 PD OE GNDXD IREF 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 CLKA CLKA CLKB ...