AR# 51047

7 Series FPGA GTX Transceivers - Recommended PLL settings for various protocols

Description

This answer record specifies the recommended PLL settings and dividers to use in 7 series FPGA GTX transceivers for the various protocols. This information will be added to the next revision (v1.6) of the 7 Series FPGAs GTX/GTH Transceivers User Guide (UG476).

Solution

Standard Line Rate Internal Data Width PLL Frequency REFCLK Frequency Using Typical REFCLK Frequency
[Gb/s] [16b/20b/32b/40b] [GHz] [MHz]
Typical N1 N2 D M
XAUI 3.125 20b 3.125 156.25 5 4 2 1
GigE 1.25 20b 2.5 125 5 4 4 1
PCIe
Optimal Jitter
5 20b 2.5 250 5 2 1 1
2.5 20b 2.5 250 5 2 2 1
5 20b 2.5 125 5 4 1 1
2.5 20b 2.5 125 5 4 2 1
PCIe
100 MHz REFCLK
5 20b 2.5 100 5 5 1 1
2.5 20b 2.5 100 5 5 2 1
CPRI 1-4X
(Multi-Rate)
2.4576 20b 2.4576 122.88 5 4 2 1
1.2288 20b 2.4576 122.88 5 4 4 1
0.6144 20b 2.4576 122.88 5 4 8 1
CPRI 1-10X
(Multi-Rate)
3.072 20b 3.072 122.88 5 5 2 1
2.4576 20b 2.4576 122.88 5 4 2 1
1.2288 20b 2.4576 122.88 5 4 4 1
0.6144 20b 2.4576 122.88 5 4 8 1
CEI 6.25 6.25 20b 3.125 390.625 4 2 1 1

Standard Line Rate Internal Data Width PLL Frequency QPLL REFCLK Frequency Using Typical REFCLK Frequency
[Gb/s] [16b/20b/32b/40b] [GHz] [Upper/Lower Band] [MHz]
Typical N
(QPLL_FBDIV,
QPLL_FBDIV_RATIO)
RXOUT_DIV (D) TXOUT_DIV (D) M
(QPLL_REFCLK_DIV)
PCIe Gen3 8 32b 8 Lower 100 80 1 1 1
CEI 6.25 6.25 20b 6.25 Lower 390.625 16 1 1 1
6.25 20b 6.25 Lower 156.25 40 1 1 1
CEI 11 9.95 32b 9.95 Upper 155.46875 64 1 1 1
11.1 32b 11.1 Upper 173.4375 64 1 1 1
SFP+
(SFF-8431,SFI)
9.8304* 32b 9.8304 Upper 122.88 80 1 1 1
9.95328 32b 9.95328 Upper 155.52 64 1 1 1
10.3125 32b 10.3125 Upper 156.25 66 1 1 1
10.5187 32b 10.5187 Upper 164.355 64 1 1 1
11.1 32b 11.1 Upper 173.4375 64 1 1 1

NOTE: * Line rate used for CPRI over SFP+ applications.

AR# 51047
Date 11/28/2012
Status Active
Type General Article
Devices