SW52212 datasheet(20/71 Pages) SILABS

Part #	SW52212

Description	12/8/4/2-Output PCI-Express Gen 1/2/3/4/5 and SRIS Clock Generator

PDF	71 Pages

Scroll/Zoom	100%

Manufacturer	SILABS [Silicon Laboratories]

Direct Link	http://www.silabs.com

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20 / 71 page

5. Functional Description

5.1 Crystal Recommendations

The clock device requires a parallel resonance crystal.

Table 5.1. Crystal Recommendations

Frequency

(Fund)

Cut

Load Cap

Shunt Cap

(max)

Motional

(max)

Tolerance

(max)

Stability

(max)

Aging (max)

25 MHz

Parallel

8–15 pF

5 pF

0.016 pF

35 ppm

30 ppm

5 ppm

5.2 Crystal Loading

Crystal loading is critical in achieving low ppm performance. To realize low ppm performance, use the total capacitance the crystal sees

to calculate the appropriate capacitive loading (CL).

The figure below shows a typical crystal configuration using the two trim capacitors. It is important that the trim capacitors are in series

with the crystal.

Figure 5.1. Crystal Capacitive Clarification

Data Sheet

Functional Description

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SW52212 Datasheet(PDF) 20 Page - Silicon Laboratories