CY24239

www.DataSheet4U.com 39 CY24239 Spread Spectrum Frequency Timing Generator Features Maximized EMI Suppression using Cypress’s Spread Spectrum Technology –1.2% and –2.4% Spread Spectrum support Three copies of CPU output Seven copies of PCI output One 48-MHz output for USB / One 24-MHz for SIO Two buffered reference outputs Two IOAPIC outputs Seventeen SDRAM outputs provide support for 4 DIMMs SMBus interface for programming Power management control inputs Table 2. Pin Selectable Frequency Input Address CPU_F, CPU1:2 FS3 FS2 FS1 FS0 (MHz) 1 1 1 1 91.66 1 1 1 0 75.0 1 1 0 1 100.0 1 1 0 0 83.3 1 0 1 1 66.6 1 0 1 0 105.0 1 0 0 1 110.0 1 0 0 0 133.3 0 1 1 1 91.66 0 1 1 0 75.0 0 1 0 1 100.0 0 1 0 0 83.3 0 0 1 1 91.66 0 0 1 0 75.0 0 0 0 1 100.0 0 0 0 0 83.3 PCI_F, PCI0:5 (MHz) 30.5 25.0 33.3 27.76 33.3 26.3 27.5 33.3 30.5 25.0 33.3 27.76 30.5 25.0 33.3 27.76 Spread Spectrum OFF OFF OFF OFF OFF OFF OFF OFF –1.2% –1.2% –1.2% –1.2% –2.4% –2.4% –2.4% –2.4% Key Specifications CPU Cycle-to-Cycle Jitter: .......................................... 250 ps CPU to CPU Output Skew: ......................................... 350 ps PCI to PCI Output Skew: ............................................ 500 ps SDRAMIN to SDRAM0:16 Delay: ..........................3.7 ns typ. VDDQ3: .................................................................... 3.3V±5% Table 1. Mode Input Table Mode 0 1 Pin 3 PCI_STOP# REF0 Block Diagram VDDQ3 REF0/(PCI_STOP#) X1 X2 XTAL OSC REF1/FS2 PLL R...