SI5325C-C-GM Datasheet, PDF (155/178 Pages) Silicon Laboratories – ANY-FREQUENCY PRECISION CLOCKS

APPENDIX G—NEAR INTEGER RATIOS
Si53xx-RM
To provide more details and to provide boundaries with respect to the “Reference vs. Output Frequency” issue
described in Appendix B on page 112, the following study was performed and is presented below.
Test Conditions
 XA/XB External Reference held constant at 38.88 MHz
 Input frequency centered at 155.52 MHz, then scanned.
Scan Ranges and Resolutions:
± 50 ppm with 2 ppm steps
± 200 ppm with 10 ppm steps
± 2000 ppm with 50 ppm steps
 Output frequency always exactly four times the input frequency
Centered at 622.08 MHz
 Jitter values are RMS, integrated from 800 Hz to 80 MHz
1200
1000
800
600
400
200
0
155.51
38.88 MHz External XA-XB Reference
155.515
155.52
Input Frequency (MHz)
155.525
Input Frequency Variation = ±50 ppm
Figure 87. ±50 ppm, 2 ppm Steps
155.53
Rev. 1.2
155