
Si53xx-RM
Rev. 0.52
123
Reference vs. Output Frequency
Because of internal coupling, output frequencies that are an integer multiple (or close to an integer multiple) of the
XA/XB reference frequency (either internal or external) should be avoided. Figure 62 illustrates this by showing a
38.88 MHz reference being used to generate both a 622.08 MHz output (which is an integer multiple of 38.88 MHz)
and 696.399 MHz (which is not an integer multiple of 38.88 MHz). Notice the mid-band spurs on the 622.08 MHz
output, which contribute to the RMS phase noise for the SONET jitter masks. Their effect is more pronounced for
the broadband case. For more information on this effect, see "Appendix G—Near Integer Ratios" on page 162.
Figure 62. Reference vs. Output Frequency
The crystal frequency of 114.285 MHz was picked for its lack of integer relationship to most of the expected output
frequencies. If, for instance, an output frequency of 457.14 MHz (= 4 x 114.285 MHz) were desired, it would be
preferable not to use the 114.285 MHz crystal as the reference. For a more detailed study of this, see "Appendix
G—Near Integer Ratios" on page 162.
Table 62. Jitter Values for Figure 62
696.399 MHz Out
622.08 MHz Out
Jitter Bandwidth
Yellow, fs RMS
Blue, fs RMS
SONET_OC48, 12 kHz to 20 MHz
379
679
SONET_OC192_A, 20 kHz to 80 MHz
393
520
SONET_OC192_B, 4 MHz to 80 MHz
210
191
SONET_OC192_C, 50 kHz to 80 MHz
373
392
Broadband, 800 Hz to 80 MHz
484
1,196
155.52 MHz in, 622.08 MHz out, 696.399 MHz out
-160
-140
-120
-100
-80
-60
-40
-20
0
100
1000
10000
100000
1000000
10000000
100000000
Offset Frequency (Hz)
P
h
ase
N
o
is
e
(d
B
c/
H
z
)
Yellow—696.399 MHz output
Blue—622.08 MHz output
Summary of Contents for Si5316 Series
Page 2: ...Si53xx RM 2 Rev 0 52 ...
Page 110: ...Si53xx RM 110 Rev 0 52 Figure 48 sfout_5 LVPECL Figure 49 sfout_6 CML ...
Page 111: ...Si53xx RM Rev 0 52 111 Figure 50 sfout_7 LVDS ...
Page 127: ...Si53xx RM Rev 0 52 127 Figure 66 155 52 MHz In 622 08 MHz Out Loop BW 7 Hz Si5324 ...
Page 128: ...Si53xx RM 128 Rev 0 52 Figure 67 19 44 MHz In 156 25 MHz Out Loop BW 80 Hz ...
Page 129: ...Si53xx RM Rev 0 52 129 Figure 68 19 44 MHz In 156 25 MHz Out Loop BW 5 Hz Si5324 ...
Page 131: ...Si53xx RM Rev 0 52 131 Figure 70 61 44 MHz In 491 52 MHz Out Loop BW 7 Hz Si5324 ...
Page 132: ...Si53xx RM 132 Rev 0 52 Figure 71 622 08 MHz In 672 16 MHz Out Loop BW 6 9 kHz ...
Page 133: ...Si53xx RM Rev 0 52 133 Figure 72 622 08 MHz In 672 16 MHz Out Loop BW 100 Hz ...
Page 134: ...Si53xx RM 134 Rev 0 52 Figure 73 156 25 MHz In 155 52 MHz Out ...
Page 139: ...Si53xx RM Rev 0 52 139 Figure 78 86 685 MHz In 173 371 MHz Out ...
Page 140: ...Si53xx RM 140 Rev 0 52 Figure 79 86 685 MHz In 693 493 MHz Out ...
Page 142: ...Si53xx RM 142 Rev 0 52 Figure 81 10 MHz In 1 GHz Out ...
Page 174: ...Si53xx RM 174 Rev 0 52 Figure 99 Si5374 Si5375 DSPLL A ...
Page 175: ...Si53xx RM Rev 0 52 175 Figure 100 Si5374 Si5375 DSPLL B ...
Page 176: ...Si53xx RM 176 Rev 0 52 Figure 101 Si5374 Si5375 DSPLL C ...