ICS9159-05 Datasheet, PDF (1/7 Pages) Integrated Circuit Systems – Frequency Generator for Pentium™/OPTi VIPER Systems

Integrated
Circuit
Systems, Inc.
ICS9159-05
Frequency Generator for Pentium^™/OPTi VIPER Systems
General Description
The ICS9159-05 is a low cost frequency generator designed
specifically for Pentium/Pentium Pro systems. The integrated
buffer minimizes skew and provides the early CPU clock required
by some chipsets such as the OPTi VIPER. A 14.318 MHz
XTAL oscillator provides the reference clock to generate
standard Pentium frequencies. The CPU clock makes gradual
frequency transitions without violating the PLL timing of
internal micro-processor clock multipliers.
The synchronous bus frequencies are selectable as CPU for
local bus or CPU/2 for PCI bus support. Green PC systems
are supported through power-down, doze, and glitch-free
stop clock modes.
Features
• Four CPU clocks operate up to 66.6 MHz at 3.3V with
glitch-free start and stop plus smooth transitions
• 3-6ns early CPU clock supports OPTi VIPER systems
• Selection of 6 frequencies, tristate, or power-down
• Six BUS clocks support local PCI bus operation
• Skew window between synchronous outputs
• Integrated buffer outputs drive up to 30pF loads
• 3.0V - 3.7V supply range
• 28-pin DIP or 28-pin 300-mil SOIC package
Block Diagram
Applications
• Ideal for green Pentium/Pentium Pro and 486 PCI
systems such as Pentium, PowerPC™ etc.
Pin Configuration
9159-05 Rev F 9/29/98
28-Pin 300-mil SOIC
Pentium is a trademark of Intel Corporaton.
PowerPC is a trademark of Motorola Corporation.
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 all
device data to verify that any