LVDS Transmitter Pre-Emphasis - LVDS Transmitter Pre-Emphasis - UG861

Spartan UltraScale+ FPGAs SelectIO Resources User Guide (UG861)

Document ID
UG861
Release Date
2026-04-28
Revision
1.1 English

The LVDS transmitter pre-emphasis (LVDS_PRE_EMPHASIS) feature allows pre-emphasis on the drivers for certain I/O standards. This attribute must be used with ENABLE_PRE_EMPHASIS.

The allowed values for the LVDS_PRE_EMPHASIS attribute are:

  • LVDS_PRE_EMPHASIS = FALSE (Default)
  • LVDS_PRE_EMPHASIS = TRUE (where ENABLE_PRE_EMPHASIS must be set to TRUE)

The LVDS_PRE_EMPHASIS attribute uses the following syntax in the XDC file:

set_property LVDS_PRE_EMPHASIS TRUE|FALSE [get_ports port_name ]

A typical pre-emphasis gain when using the LVDS_PRE_EMPHASIS attribute is listed in the following table.

Table 1. Typical Pre-Emphasis Gain when Using the LVDS_PRE_EMPHASIS Attribute
Attribute Value Estimated Gain (dB)
LVDS_PRE_EMPHASIS (HP I/O banks only) TRUE 1 4
  1. ENABLE_PRE_EMPHASIS must be set to TRUE.