10

PS9023A

11/20/09

PI6C49003

Networking Clock Generator

Notes:

1. Measured at the end of an 8-inch trace with a 5pF load.

2. Measurement taken from a single-ended waveform.

3. Measurement taken from a differential waveform.

4. Measured from -150 mV to +150 mV on the differential waveform. The signal is monotonic through the

measurement region for rise and fall time. The 300 mV measurement window is centered on the differen-

tial zero crossing.

5. Measured at crossing point where the instantaneous voltage value of the rising edge of 100M+ equals the

falling edge 100M

–.

6. Refers to the total variation from the lowest crossing point to the highest, regardless of which edge is cross-

ing. Refers to all crossing points for this measurement.

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 ad-

ditional +2500 PPM nominal shift in maximum period resulting from the -0.5% down spread.

09-0097