11

www.pericom.com

PI6C49016

Rev. B

06/25/13

PI6C49016

Low Power Networking Clock Generator

7. Defines as the absolute minimum or maximum instantaneous period. This includes cycle-to-cycle jitter, relative PPM tolerance,

and spread spectrum modulation.

8. Defined as the total variation of all crossing voltages of rising 100M+ and falling 100M–.

9. Refer to section 4.3.2.1 of the PCI Express Base Specification, Revision 1.1 for information regarding PPM considerations.

10. PPM refers to parts per million and is a DC absolute period accuracy specification. 1 PPM is 1/1,000,000th of 100 MHz exactly or 100 Hz. For 300 PPM there

is an error budget of 100Hz/PPM * 300 PPM = 30 kHz. The period is measured with a frequency counter with measurement window set at 100 ms or greater. With

spread spectrum turned off the error is less than ±300 ppm. With spread spectrum turned on there is an additional +2500 PPM nominal shift in maximum period

resulting from the -0.5% down spread.

11. Matching applies to rising edge rate for PCIe and falling edge rate for PCIeN. It is measured using a ±75 mV window centered on the median cross point where

PCIe rising meets PCIeN falling. The median cross point is used to calculate the voltage thresholds the oscilloscope is to use for the edge rate calculations. The

rising edge rate of PCIe should be compared to the falling edge rate of PCIeN. The maximum allowed difference should not exceed 20% of the slowest edge rate.

Notes (Continued)

13-0102