MK1432

MK1432/MK1434 Green PC and Local Bus Clock Source Description The MK1432 and MK1434 are low cost, high performance triple clock synthesizers for green PC and local bus desktop and notebook applications. 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 selectable 2XCPU and CPU, selectable local bus clock, ISA clock, and one fixed peripheral clock. The chips support PCI and VL buses. The fixed clock is either 24MHz or 40MHz. The devices can operate at 5V or 3.3V up to and including 80MHz on the 2XCPU clock. The Power Saving pin causes the CPU clocks to smoothly transition to 33.33 MHz for Pentiums, and 16.67 MHz for 486DX4. In addition, a single pin can be made to slow DX2s to 8 MHz. Features Packaged in 16 pin narrow (150 mil) SOIC Supports all Pentium ™ Processor timing specs Supports synchronous and asynchronous local bus Selectable local bus frequencies of 25, 33, or 50MHz SCSI or VL bus 40MHz clock on MK1434 Floppy or super I/O clock on MK1432 Single Power Saving pin switches to low power mode (for 486 and Pentium) 5V or 3.3V (up to 80MHz) operation Smooth transitions for Pentium and 486 based Green PC Low skew (<250ps) Pentium compatible 2X and 1X outputs Duty cycle of 45/55 up to 100 MHz 25mA output drive capability at TTL levels Compatible with all popular microprocessors Packaged in 16 pin narrow SOIC For Early Clock support, consul...