Xilinx Virtex-6 FPGA User Manual page 190

Chapter 4: Receiver
Table 4-7
shows the Use Mode 4 configuration.
Table 4-7: RX Termination Use Mode 4 Configuration and Notes
External
Use Mode AC
Voltage
Coupling
4 OFF
X-Ref Target - Figure 4-6
Board
www.BDTIC.com/XILINX
190
outlines the recommended settings for RX termination in Use Mode 4.
Term Internal AC Internal
Coupling Bias
V OFF 800 mV
TT
FPGA
MGTAVTT_*
ESD Diodes
nominal
50Ω
nominal
50Ω
MGTAVTT_*
ESD Diodes
Figure 4-6: RX Termination Use Mode 4 Configuration
www.xilinx.com
Max
Swing Suggested Protocols and Usage Notes
mV
DPP
1200 Protocol: Custom GTX-GTX chip-to-chip
interface
Attribute Settings:
AC_CAP_DIS = TRUE
RCV_TERM_GND = FALSE
RCV_TERM_VTTRX = TRUE
Notes:
Recommended for use if the TX termination
voltage is 1.2V. If the TX termination voltage is
not 1.2V, DC current will result with possible
signal distortion. This allows for DC coupling
on the board. Not recommended for the
backplane due to interoperability with SerDes
where the TX termination voltage is not 1.2V.
nominal 7 pF
nominal
50 KΩ
MGTAVTT_*
nominal
50 KΩ
nominal 7 pF
Virtex-6 FPGA GTX Transceivers User Guide
Figure 4-6
V
CM
2/3 MGTAVTT_*
UG366_c4_06_120909
UG366 (v2.5) January 17, 2011