Termination Options - Termination Options - UG861

Spartan UltraScale+ FPGAs SelectIO Resources User Guide (UG861)

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

The AMD Vivado™ Design Suite can perform simultaneous switching noise (SSN) analysis for each design, taking into account the actual I/O standards and options assigned to the I/O pins in the target device and package.

For each output pin, there is the option to specify whether or not termination is present on the board. The off-chip termination field automatically populates with the default terminations for each I/O standard, if one exists.

The following table lists all of the default terminations for each of the I/O standards supported by Spartan UltraScale+ devices when using the SSN predictor tool within the Vivado Design Suite. For each I/O pin in the design, you can specify whether to use these terminations, or to have no termination.

Table 1. Default Terminations for SSN Noise Analysis by I/O Standard
I/O Standard Drive Termination Option
DIFF_HSTL_I Far VTT 40 Ω
DIFF_HSTL_I_12 Far VTT 40 Ω
DIFF_HSTL_I_DCI_12 Far VTT 40 Ω
DIFF_HSTL_I_18 Far VTT 50 Ω
DIFF_HSTL_I_DCI Far VTT 40 Ω
DIFF_HSTL_I_DCI_18 Far VTT 50 Ω
DIFF_HSTL_II Near VTT 50 Ω & Far VTT 50 Ω
DIFF_HSUL_12 None
DIFF_HSUL_12_DCI None
DIFF_POD10 Far VCCO 40 Ω
DIFF_POD10_DCI Far VCCO 40 Ω
DIFF_POD12 Far VCCO 40 Ω
DIFF_POD12_DCI Far VCCO 40 Ω
DIFF_SSTL12 Far VTT 40 Ω
DIFF_SSTL12_DCI Far VTT 40 Ω
DIFF_SSTL135 Far VTT 40 Ω
DIFF_SSTL135_DCI Far VTT 40 Ω
DIFF_SSTL135_R Far VTT 40 Ω
DIFF_SSTL15 Far VTT 40 Ω
DIFF_SSTL15_DCI Far VTT 40 Ω
DIFF_SSTL15_R Far VTT 50 Ω
DIFF_SSTL18_I Far VTT 50 Ω
DIFF_SSTL18_I_DCI Far VTT 50 Ω
HSLVDCI_15 None
HSLVDCI_18 None
HSTL_I Far VTT 40 Ω
HSTL_I_12 Far VTT 40 Ω
HSTL_I_DCI_12 Far VTT 40 Ω
HSTL_I_18 Far VTT 50 Ω
HSTL_I_DCI Far VTT 40 Ω
HSTL_I_DCI_18 Far VTT 50 Ω
HSUL_12 None
HSUL_12_DCI None
LVCMOS12 2 None
LVCMOS12 4 None
LVCMOS12 6 None
LVCMOS12 8 None
LVCMOS12 12 Far VTT 50 Ω
LVCMOS15 2 None
LVCMOS15 4 None
LVCMOS15 6 None
LVCMOS15 8 None
LVCMOS15 12 Far VTT 50 Ω
LVCMOS15 16 Far VTT 50 Ω
LVCMOS18 2 None
LVCMOS18 4 None
LVCMOS18 6 None
LVCMOS18 8 None
LVCMOS18 12 Far VTT 50 Ω
LVCMOS18 16 Far VTT 50 Ω
LVCMOS25 4 None
LVCMOS25 8 None
LVCMOS25 12 Far VTT 50 Ω
LVCMOS25 16 Far VTT 50 Ω
LVCMOS33 4 None
LVCMOS33 8 None
LVCMOS33 12 Far VTT 50 Ω
LVCMOS33 16 Far VTT 50 Ω
LVDCI_15 None
LVDCI_18 None
LVDS Far Differential 100 Ω
LVDS_PE Far Differential 100 Ω
LVTTL 4 None
LVTTL 8 None
LVTTL 12 Far VTT 50 Ω
LVTTL 16 Far VTT 50 Ω
MINI_LVDS_25 Far Differential 100 Ω
POD10 Far VCCO 40 Ω
POD10_DCI Far VCCO 40 Ω
POD12 Far VCCO 40 Ω
POD12_DCI Far VCCO 40 Ω
SSTL12 Far VTT 40 Ω
SSTL12_DCI Far VTT 40 Ω
SSTL135 Far VTT 40 Ω
SSTL135_DCI Far VTT 40 Ω
SSTL135_R Far VTT 40 Ω
SSTL15 Far VTT 40 Ω
SSTL15_DCI Far VTT 40 Ω
SSTL15_R Far VTT 50 Ω
SSTL18_I Far VTT 50 Ω
SSTL18_I_DCI Far VTT 50 Ω

The following figure illustrates each of these terminations.

Figure 1. Default Terminations