ICS9147-22 Datasheet | Integrated Circuit Systems

Integrated Circuit Systems, Inc. Pentium/Pro TM System and Cyrix™ Clock Chip General Description The ICS9147-22 is a Clock Synthesizer chip for Pentium and Pentium Pro plus Cyrix CPU based Desktop/Notebook systems that will provide all necessary clock timing. Features include four CPU, seven PCI and eight SDRAM clocks. Two reference outputs are available equal to the crystal frequency, plus the IOAPIC output powered by VDDL. Additionally, the device meets the Pentium powerup stabilization, which requires that CPU and PCI clocks be stable within 2ms after power-up. High drive PCICLK and SDRAM outputs typically provide greater than 1 V/ns slew rate into 30 p F loads. CPUCLK outputs typically provide better than 1V/ns slew rate into 20 p F loads while maintaining 50 ± 5% duty cycle. The REF clock outputs typically provide better than 0.5V/ns slew rates. The ICS9147-22 accepts a 14.318MHz reference crystal or clock as its input and runs on a 3.3V supply. Features • • • • • • • Generates system clocks for CPU, IOAPIC, SDRAM, PCI, plus 14.318 MHz (REF0:1), USB, Super I/O Supports single or dual processor systems Supports Intel 60, 66.8MHz, Cyrix 55, 75MHz plus 83.3 and 68MHz (Turbo of 66.6) speeds. Synchronous clocks skew matched to 250ps window on CPU, SDRAM and 500ps window on PCI clocks CPU clocks to PCI clocks skew 1-4ns (CPU early) Two fixed outputs, 48MHz and 24 MHz Separate 2.5V and 3.3V supply pins - 2.5V or 3.3V output: CPU, IOAPIC - 3.3V outputs: SDRAM, PCI, REF, 48/24 MHz No power supply sequence requirements 48 pin 300 mil SSOP • • Pin Configuration Block Diagram 48-Pin SSOP Power Groups VDD1 = REF (0:1), X1, X2 VDD2 = PCICLK_F, PCICLK (0:5) VDD3 = SDRAM (0:7), VDD4 = 48MHz, 24MHz VDDL = IOAPIC, CPUCLK (0:3) Pentium is a trademark on Intel Corporation. 9147-22 Rev A 072597P ICS reserves the right to make changes in the device data identified in this publication without further notice. ICS advises its customers to obtain the latest version of...