MK1442

MK1442/MK1443 SCSI and Ethernet Clock Source Description The MK1442/3 are the ideal way to generate clocks for desktop computer motherboards and LAN workstations. Using analog Phase-Locked Loop (PLL) techniques, the devices accept a 14.318 MHz crystal input to produce multiple output clocks up to 100 MHz. They provide 2XCPU, CPU, floppy controller, keyboard, system, SCSI and Ethernet clocks. The MK1442/3 are perfect for new Pentium™ Processor, PCI bus and 486 systems. The devices can operate at 5V or 3.3V up to and including 80MHz on the CPU clock. The devices are identical except the MK1442 has an Output Enable (OE) pin that tri-states all outputs when taken low, and the MK1443 has an extra 14.318 MHz clock. Features Provides exact frequency Ethernet and SCSI clocks 5V or 3.3V (up to 80MHz) operation Output clock frequencies up to 100 MHz Pentium™ Processor compatible timing 486 compatible smooth frequency transitions Seven or eight output clocks Compatible with X86 and 680X0 CPUs Skew controlled 2X and 1X CPU to within 250ps Packaged in 16 pin skinny SOIC or PDIP Duty cycle of 47.5/52.5 up to 66.66 MHz Duty cycle of 45/55 up to 100 MHz Total of 15 different selectable CPU frequencies Tri-state outputs for board level testing 25mA drive capability at TTL levels Keyboard frequencies of 12MHz (-01), 8MHz (-02), or 16MHz (-03) Advanced, low power CMOS process MK1442 - output enable MK1443 - two 14.318 MHz outputs Block Diagram VDD GND CPUS...