CY2267

The CY2267 is a low-cost Clock Synthesizer/Driver chip for a Pentium, Pentium Pro, or Cyrix 6x86-based motherboard.

The CY2267 outputs sixteen CPU clocks, twelve of which can be used to support up to three SDRAM modules. The PCI clock output can be buffered with an external, low-cost Zero Delay Buffer (CY2305/9), thus providing a complete solution for 82430TX desktop systems.

The CPU clocks of the CY2267 have less than 200 ps cycle- to-cycle jitter. Both the CPU and PCI clocks have a slew rate of greater than 1V/ns. The USB clock meets Intel's accuracy, jitter, and rise and fall time requirements.

All CPU clocks support fast clock stabilization on power-up (< 2 ms). Additionally, two dedicated Frequency Select inputs are used for Output Enable control and setting the CPU clock output frequencies.

The CY2267 clock outputs are designed for low EMI emissions.

Controlled rise and fall times, unique output driver circuits, and innovative circuit layout techniques enable the CY2267 to have lower EMI than clock devices from other manufacturers.

Please refer to the application note "Layout and Termination Techniques for Cypress Clock Generators" for more information on recommended system layout techniques.

The CY2267 accepts a 14.318 MHz reference crystal or clock as its input and runs off a 3.3V supply. The CY2267 is available in a space-saving, low-cost 34-pin SSOP package and is pin-compatible with the CY2264 and CY2265.