SI52112-B3 Datasheet, PDF (7/20 Pages) Silicon Laboratories – PCI-EXPRESS GEN 2 DUAL OUTPUT CLOCK GENERATOR

Si52112-B3/B4
2. Crystal Recommendations
If using a crystal input, the device requires a parallel resonance crystal.
Table 6. Crystal Recommendations
Frequency Cut Loading Load Cap ESR Drive Shunt Motional Tolerance Stability Aging
(Fund)
Cap (max) (max) (max) _{(max) (max)}
25 MHz AT Parallel 12–15 pF <50  >150 µW 5 pF 0.016 pF 35 ppm 30 ppm 5 ppm
2.1. 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 (C_L).
Figure 1 shows a typical crystal configuration using two trim capacitors. It is important that the trim capacitors are in
series with the crystal.
Figure 1. Crystal Capacitive Clarification
Rev 1.2
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