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Table 1-42: SLEW Attribute for All Single-Ended and Differential HSTL, SSTL, HSUL, and Mobile_DDR
IOSTANDARDs
IBUF, IBUFG, IBUFDS, IBUFGDS,
Attribute
IBUFDS_DIFF_OUT, or IBUFGDS_DIFF_OUT
HP I/O Banks
SLEW
N/A
LVDS and LVDS_25 (Low Voltage Differential Signaling)
Low-voltage differential signaling (LVDS) is a powerful high-speed interface in many
system applications. 7 series FPGA I/Os are designed to comply with the EIA/TIA
electrical specifications for LVDS to make system and board design easier. With the use of
an LVDS current-mode driver in the IOBs and the optional internal differential termination
feature, the need for external source termination in point-to-point applications is
eliminated. 7 series devices provide the most flexible solution for doing an LVDS design in
an FPGA.
The LVDS I/O standard is only available in the HP I/O banks. It requires a V
powered at 1.8V for outputs and for inputs when the optional internal differential
termination is implemented (DIFF_TERM = TRUE).
The LVDS_25 I/O standard is only available in the HR I/O banks. It requires a V
powered at 2.5V for outputs and for inputs when the optional internal differential
termination is implemented (DIFF_TERM = TRUE).
Table 1-43: Available I/O Bank Type
Transmitter Termination
The 7 series FPGA LVDS transmitter does not require any external termination.
lists the allowed attributes corresponding to the 7 series FPGA LVDS current-mode
drivers. 7 series FPGA LVDS current-mode drivers are a true current source and produce
the proper (EIA/TIA compliant) LVDS signal.
Receiver Termination
Figure 1-70
board with 50Ω transmission lines.
7 Series FPGAs SelectIO Resources User Guide
UG471 (v1.10) May 8, 2018
HR I/O Banks
N/A
HR
Available for LVDS_25 only
is an example of differential termination for an LVDS or LVDS_25 receiver on a
www.xilinx.com
Supported I/O Standards and Terminations
Primitives
OBUF, OBUFT, OBUFDS, or OBUFTDS, IOBUF,
IOBUFDS or IOBUFDS_DIFF_OUT
HP I/O Banks
{FAST, SLOW}
HP
Available for LVDS only
HR I/O Banks
{FAST, SLOW}
to be
CCO
to be
CCO
Table 1-44
91
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