SI5315 Datasheet, PDF (40/54 Pages) Silicon Laboratories – Provides jitter attenuation and frequency translation between SONET/PDH and Ethemet

Si5315
7.1.2. Reference Jitter
Jitter on the reference input has a roughly one-to-one transfer function to the output jitter over the bandwidth
ranging from 100 Hz up to 30 kHz. If a crystal is used on the XA/XB pins, the reference will have low jitter if a
suitable crystal is in use. If the XA/XB pins are connected to an external reference oscillator, the jitter of the
external reference oscillator may contribute significantly to the output jitter.
A typical reference input-to-output jitter transfer function is shown in Figure 21.
Jitter Transfer XA/XB Reference to CKOUT
38.88 MHz XO, 38.88 MHz CKIN, 38.88 MHz CKOUT
5
0
-5
-10
-15
-20
-25
-30
1
10
100
1000
10000
100000 1000000
Jitter Frequency (Hz)
Figure 21. Typical XA/XB Reference Jitter Transfer Function
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Rev. 1.0