MK1491-14

www.DataSheet4U.com MK1491-14 OPTi ACPI Firestar Clock Source Description The MK1491-14 is a low cost, low jitter, high performance clock synthesizer for OPTi’s Firestar and Firestar+ chipsets for Pentium™ Processor-based mobile computer applications. Using analog Phase-Locked Loop (PLL) techniques, the device uses a 14.318 MHz crystal input to produce multiple output clocks up to 75 MHz. It provides selectable Host and PCI local bus clocks as well as selectable clocks for Super I/O or Universal Serial Bus (USB). The device has up to seven Host output clocks. The chip has three different power down modes that reduce power on various clocks. Features Packaged in 28 pin, 150 mil wide SSOP Provides all critical timing for OPTi ACPI Firestar and Firestar+ Early Host clock of 3.5ns Separate VDD and skew adjust for Host 5,6, and 7 supports field upgrade to Firestar+ and new 2.5V processors 48MHz USB, 24MHz SIO, and Audio clock support Single pin CPU(Host) slowdown to 33.3MHz Multiple power down modes Low EMI Enable pin reduces EMI radiation (patent pending) Block Diagram VDD 3 FS1:0 Synch./Asynch. PCI STOP# SLOW# Low EMI Enable PS GND 4 VDD HOST5-7 HS VDD HOST1-4 Output Buffers HOST/PCI Clocks 4 HOST1:4 2 Output Buffers Host/2 MUX Output Buffers Output Buffer Output Buffer 5 HOST 5, 7 EHOST6 PCI 1:5 SEL0 SEL1 33M Fixed Clock F1 F2 14.31818 MHz crystal XI Crystal Oscillator XO Output Buffer 14.318 MHz MDS 1491-14 B 1 Revision 061801 Integrated Cir...