System Peripheral Clock Source

The ICS650-21 is a low cost, low-jitter, high-performance clock synthesizer for system peripheral applications. Using analog/digital Phase Locked Loop (PLL) techniques, the device accepts a parallel resonant 25 MHz crystal input to produce up to eight output clocks. The device provides clocks for PCI, SCSI, Fast Ethernet, Ethernet, USB, and AC97. The user can select one of three USB frequencies and also one of two AC97 audio frequencies. The OE pin puts all outputs into a high-impedance state for board leveltesting. All frequencies are generated with less than one ppm error, meeting the demands of SCSI and Ethernet clocking.