ICS9147-16

Integrated Circuit Systems, Inc. ICS9147-16 Frequency Generator & Integrated Buffers for PENTIUMTM General Description The ICS9147-16 generates all clocks required for high speed RISC or CISC microprocessor systems such as Intel PentiumPro. Two different reference frequency multiplying factors are externally selectable with smooth frequency transitions. Glitch-free Stop clock control is provided for CPU and BUS clocks. Complete chip low current mode is achieved with the Power Down# pin. High drive BUS outputs typically provide greater than 1 V/ ns slew rate into 30 pF loads. CPU outputs typically provide better than 1V/ns slew rate into 20 pF loads while maintaining 50± 5% duty cycle. The REF and IOAPIC clock outputs typically provide better than 0.5V/ns slew rates. Separate buffer supply pins VDDL allow for nominal 3.3V voltage or reduced voltage swing (from 2.9 to 2.5V) for CPU (1:4) and IOAPIC outputs. Features • • • • • • • Generates four processor, eight bus, four 14.31818 MHz, two 48 MHz clocks for USB support. CPU to BUS clock skew 1 to 4ns (CPU early) Synchronous clocks skew matched to 250ps window on CPU and 500ps window on BUS. Selectable multiplying ratios Glitch free stop clock controls CPUEN and BUSEN 3.0V – 3.7V supply range, 2.5V to VDD supply range for CPU (1:4) clocks and IOAPIC clock. 48-pin SSOP package Pin Configuration Block Diagram 48-Pin SSOP Pentium is a trademark of Intel Corporation 9147-16 Rev A 072897P ICS reserves the right to make changes...