Xilinx Virtex-6 FPGA

202 www.xilinx.com Virtex-6 FPGA GTX Transceivers User Guide
UG366 (v2.5) January 17, 2011
Chapter 4: Receiver
Table 4-18 provides DFETAP1 and RXEQMIX settings for 4.25 Gb/s operation for
backplane applications.
Table 4-19 provides DFETAP1 and RXEQMIX settings for 5 Gb/s operation for backplane
applications.
60 [1524.0]
(4)
13.6 0 0
Notes:
1. GTX TXDIFFCTRL = 4'b1010, TXPOSTEMPHASIS = 5'b00000, and
TXPREEMPHASIS = 4'b0000.
2. Nominal 24 inches [609.6 mm] trace length = 6 inches [152.4 mm] backplane + 2 HmZD or eHSD
connectors (trace length neglected) + 18 inches [457.2 mm] on line cards.
3. Nominal 40 inches [1016.0 mm] trace length = 20 inches [508 mm] backplane + 2 HmZD or eHSD
connectors (trace length neglected) + 20 inches [508 mm] on line cards.
4. Nominal 60 inches [1524.0 mm] trace length = 40 inches [1016 mm] backplane + 2 HmZD or eHSD
connectors (trace length neglected) + 20 inches [508 mm] on line cards.
Table 4-18: DFETAP1 and RXEQMIX at 4.25 Gb/s for Backplane Applications
Nominal Trace
Length on FR4
Substrate
(inches [mm])
Loss (dB) @
2.125 GHz
TAP1
RXEQMIX = 000 RXEQMIX = 010 RXEQMIX = 110
24 [609.6]
(2)
9.9 00
40 [1016.0]
(3)
12.7 50
60 [1524.0]
(4)
17.2 5 5
Notes:
1. GTX TXDIFFCTRL = 4'b1010, TXPOSTEMPHASIS = 5'b00000, and
TXPREEMPHASIS = 4'b0000.
2. Nominal 24 inches [609.6 mm] trace length = 6 inches [152.4 mm] backplane + 2 HmZD or eHSD
connectors (trace length neglected) + 18 inches [457.2 mm] on line cards.
3. Nominal 40 inches [1016.0 mm] trace length = 20 inches [508 mm] backplane + 2 HmZD or eHSD
connectors (trace length neglected) + 20 inches [508 mm] on line cards.
4. Nominal 60 inches [1524.0 mm] trace length = 40 inches [1016 mm] backplane + 2 HmZD or eHSD
connectors (trace length neglected) + 20 inches [508 mm] on line cards.
Table 4-19: DFETAP1 and RXEQMIX at 5 Gb/s for Backplane Applications
Nominal Trace
Length on FR4
Substrate
(inches [mm])
Loss (dB) @
2.5 GHz
TAP1
RXEQMIX = 000 RXEQMIX = 010 RXEQMIX = 110
24 [609.6]
(2)
12.2 00
40 [1016.0]
(3)
15.1 10 0
Table 4-17: DFETAP1 and RXEQMIX at 3.125 Gb/s for Backplane
Applications (Cont’d)
Nominal Trace
Length on FR4
Substrate
(inches [mm])
Loss (dB) @
1.5625 GHz
TAP1
RXEQMIX = 000 RXEQMIX = 010 RXEQMIX = 110
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