Silicon Laboratories SI5375 - Manual (Page 117)

Si53xx-RM
Rev. 1.2 117
High Reference Frequency
When selecting a reference frequency, with all other things being equal, the higher the reference frequency, the
lower the output jitter. Figures 65 and 66 compare the results with a 114.285 MHz crystal versus a 40 MHz crystal.
For a discussion of the available reference frequencies, see section " Resonator/External Clock Selection" on page
108.
Figure 65. 622.08 MHz Output with a 114.285 MHz Crystal
Jitter Band Jitter, RMS
SONET_OC48, 12 kHz to 20 MHz 242 fs
SONET_OC192_A, 20 kHz to 80 MHz 269 fs
SONET_OC192_B, 4 to 80 MHz 166 fs
SONET_OC192_C, 50 kHz to 80 MHz 265 fs
Brick Wall_800 Hz to 80 MHz 270 fs
*Note: Jitter integration bands include low-pass (–20 dB/Dec) and hi-pass
(–60 dB/Dec) roll-offs per Telcordia GR-253-CORE.