CY2277A

www.DataSheet4U.com 7A CY2277A Pentium®/II, 6x86, K6 Clock Synthesizer/Driver for Desktop/ Mobile PCs with Intel® 82430TX and 2 DIMMs or 3 SO-DIMMs Features Mixed 2.5V and 3.3V operation Complete clock solution to meet requirements of Pentium®, Pentium® II, 6x86, or K6 motherboards — Four CPU clocks at 2.5V or 3.3V — Up to eight 3.3V SDRAM clocks — Seven 3.3V synchronous PCI clocks, one free running — Two 3.3V USB/IO clocks at 48 or 24 MHz, selectable by serial interface — One 2.5V IOAPIC clock at 14.318 MHz — Two 3.3V Ref. clocks at 14.318 MHz Factory-EPROM programmable CPU, PCI, and USB/IO clock frequencies for custom configuration Factory-EPROM programmable output drive and slew rate for EMI customization MODE Enable pin for CPU_STOP and PCI_STOP SMBus serial configuration interface Available in space-saving 48-pin SSOP and TSSOP packages. The CY2277A has power-down, CPU stop and PCI stop pins for power management control. The CPU stop and PCI stop are controlled by the MODE pin. They are multiplexed with SDRAM clock outputs, and are selected when the MODE pin is driven LOW. Additionally, these inputs are synchronized on-chip, enabling glitch-free transitions. When the CPU_STOP input is asserted, the CPU outputs are driven LOW. When the PCI_STOP input is asserted, the PCI outputs (except the free-running PCI clock) are driven LOW. Finally, when the PWR_DWN pin is asserted, the reference oscillator and PLLs are shut down, and all outputs are driven LOW. The...