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

Applications
• Ideal for green Pentium/Pentium Pro and 486 PCI systems such as Pentium, PowerPC™ etc.