CertusPro-NX SerDes/PCS Usage Guide
Preliminary
Technical Note
FPGA-TN-02245-0.81
© 2020-2021 Lattice Semiconductor
161
All rights reserved. CONFIDENTIAL
Appendix C. Calculating Parameters for SerDes PLL
lists the recommended parameters for SerDes PLL in specific data rate. For detailed information about PLL
clock setting, refer to
section. N need be set as 5, 10 or 20, when 8B/10B PCS is required.
Table C. 1. Recommended Parameters for SerDes PLL
Bit Rate
(Gbps)
Reference Clock
(MHz)
M
F
N
F
VCO
(MHz)
F
bit
(MHz)
F
PMA
(MHz)
Note
0.27
135
8
1
8
8640
1080
135
Actual data rate is 1.08Gbps
0.6144
76.8
8
1
8
4915.2
614.4
76.8
PMA Only
122.88
8
1
5
4915.2
614.4
122.88
Risk for 4915.2MHz F
VCO
1.001
100.1
8
1
10
8008
1001
100.1
—
125.125
1
8
1
8
8008
1001
125.125
PMA Only
1.152
76.8
8
3
5
9216
1152
230.4
—
115.2
8
1
10
9216
1152
115.2
—
144
8
1
8
9216
1152
144
PMA Only
1.188
74.25
8
1
16
9504
1188
74.25
PMA Only
74.25
8
2
8
9504
1188
148.5
PMA Only
79.2
8
3
5
9504
1188
237.6
—
118.8
8
1
10
9504
1188
118.8
—
148.5
8
1
8
9504
1188
148.5
PMA Only
1.2288
76.8
8
1
16
9830.4
1228.8
76.8
PMA Only
76.8
8
2
8
9830.4
1228.8
153.6
PMA Only
81.92
8
3
5
9830.4
1228.8
245.76
—
122.88
8
1
10
9830.4
1228.8
122.88
—
153.6
8
1
8
9830.4
1228.8
153.6
PMA Only
1.25
78.125
8
1
16
10000
1250
78.125
PMA Only
78.125
8
2
8
10000
1250
156.25
PMA Only
83.333
8
3
5
10000
1250
250
—
125
8
1
10
10000
1250
125
—
156.25
8
1
8
10000
1250
156.25
PMA Only
1.485
74.25
4
2
10
5940
1485
148.5
—
74.25
4
4
5
5940
1485
297
—
92.8125
1
4
1
16
5940
1485
92.8125
PMA Only
92.8125
1
4
2
8
5940
1485
185.625
PMA Only
99
4
3
5
5940
1485
297
—
148.5
4
1
10
5940
1485
148.5
—
148.5
4
2
5
5940
1485
297
—
1.5
75
4
4
5
6000
1500
300
—
75
4
2
10
6000
1500
150
—
93.75
4
1
16
6000
1500
93.75
PMA Only
93.75
4
2
8
6000
1500
187.5
PMA Only
100
4
3
5
6000
1500
300
—
150
4
2
5
6000
1500
300
—
150
4
1
10
6000
1500
150
—
1.62
81
4
1
20
6480
1620
81
—
81
4
2
10
6480
1620
162
—
101.25
1
4
1
16
6480
1620
101.25
PMA Only
101.25
1
4
2
8
6480
1620
202.5
PMA Only
108
4
3
5
6480
1620
324
—