CY2280

0 CY2280 100-MHz Pentium® II Clock Synthesizer/Driver with Spread Spectrum for Mobile or Desktop PCs Features Mixed 2.5V and 3.3V operation Clock solution for Pentium® II, and other similar processor-based motherboards — Four 2.5V CPU clocks up to 100 MHz — Eight 3.3V sync. PCI clocks, one free-running — Two 3.3V 48-MHz USB clocks — Three 3.3V Ref. clocks at 14.318 MHz — Two 2.5V APIC clocks at 14.318 MHz or PCI/2 EMI control — Spread spectrum clocking — Factory-EPROM programmable spread spectrum margin — Factory-EPROM programmable output drive and slew rate Factory-EPROM programmable CPU clock frequencies for custom configurations Available in space-saving 48-pin SSOP package Functional Description The CY2280 is a Spread Spectrum clock synthesizer/driver for a Pentium II, or other similar processor-based PC requiring 100-MHz support. All of the required system clocks are provided in a space-saving 48-pin SSOP package. The CY2280 can be used with the CY231x for a total solution for systems with SDRAM. The CY2280 provides the option of spread spectrum clocking on the CPU and PCI clocks for reduced EMI. A downspread percentage is introduced when the SEL_SS input is asserted. The device can be run without spread spectrum when the SEL_SS input is deasserted. The percentage of spreading is EPROM-programmable to optimize EMI-reduction. The CY2280 has power-down, CPU stop, and PCI stop pins for power management control. The signals are synchronized on-chip, and ensure g...