557G-05ALFT Renesas

DATASHEET QUAD DIFFERENTIAL PCI-EXPRESS GEN1 CLOCK SOURCE ICS557-05A Description Features The ICS557-05A is a spread-spectrum clock generator that Packaged in 20-pin TSSOP supports PCI-Express requirements. It is used in PC or RoHS 5 (green) or RoHS 6 (green and lead free) embedded systems to substantially reduce complaint package electro-magnetic interference (EMI). The device provides Supports PCI-Express applications four differential HCSL or LVDS high-frequency outputs with spread spectrum capability. The output frequency and Four differential spread spectrum clock outputs spread type are selectable using external pins. 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 For PCIe Gen2 applications, see the 5V41066 For PCIe Gen3 applications, see the 5V41236 Block Diagram VDD PD OE 2 Spread Spread Spectrum/ 3 Spectrum Output SEL 2:0 clock Circuitry selection CLKOUTA X1 CLKOUTA 25 MHz Clock CLKOUTB crystal or Oscillator PLL Clock CLKOUTB clock Synthesis X2 CLKOUTC CLKOUTC Optional tuning crystal CLKOUTD capacitors CLKOUTD 2 Rr(IREF) GND IDT QUAD DIFFERENTIAL PCI-EXPRESS GEN1 CLOCK SOURCE 1 ICS557-05A REV O 112111ICS557-05A QUAD DIFFERENTIAL PCI-EXPRESS GEN1 CLOCK SOURCE PCIE SSCG Pin Assignment 1 20 CLKA VDDXD S0 2 19 CLKA S1 3 18 CLKB S2 4 17 CLKB X1 5 16 GNDODA X2 6 15 VDDODA PD 7 14 CLKC OE 8 13 CLKC GNDXD 9 12 CLKD IREF 10 11 CLKD 20-pin (173 mil) TSSOP Spread Spectrum Selection Table S2 S1 S0 Spread% Spread Type Output Frequency 0 0 0 -0.5 Down 100 0 0 1 -1.0 Down 100 0 1 0 -1.5 Down 100 0 1 1 No Spread Not Applicable 100 1 0 0 -0.5 Down 200 1 0 1 -1.0 Down 200 1 1 0 -1.5 Down 200 1 1 1 No Spread Not Applicable 200 IDT QUAD DIFFERENTIAL PCI-EXPRESS GEN1 CLOCK SOURCE 2 ICS557-05A REV O 112111