Internal Differential Termination Behavior in Differential I/O Standards

UltraScale Architecture SelectIO Resources User Guide (UG571)

Document ID
UG571
Release Date
2022-08-31
Revision
1.14 English

The internal differential termination (100W) is turned on in the driver and bidirectional modes of operation (default) for these I/O standards: LVDS, LVDS_25, SLVS_400_18, SLVS_400_25, SUB_LVDS, PPDS_25, RSDS_25, and MINI_LVDS_25. The behavior of internal differential termination in bidirectional mode and the input or output modes of operation are listed in Table: Internal Differential Termination Behavior In Differential I/O Standards .

Table 1-76:      Internal Differential Termination Behavior In Differential I/O Standards 

Primitive(1)

Driving

3-state/Receiving

OBUFDS

Internal differential termination is ON

N/A

OBUFTDS

Internal differential termination is ON

Internal differential termination is ON.

IBUFDS

N/A

When DIFF_TERM = TRUE or DIFF_TERM_ADV = TERM_100, then internal differential termination is ON.

When DIFF_TERM = FALSE or DIFF_TERM_ADV = TERM_NONE, then internal differential termination is OFF.

IOBUFDS

Internal differential termination is ON

Internal differential termination is ON, irrespective of the DIFF_TERM or DIFF_TERM_ADV attributes.

DIFF_TERM = TRUE or FALSE

DIFF_TERM_ADV = TERM_100 or TERM_NONE

Notes:

1.Support is implied for primitives that are derivatives of the primitives listed (for example, *_DIFF_OUT, *_DCIEN, *_IBUFDISABLE, or *_INTERMDISABLE). Refer to the SelectIO Interface Primitives section for all supported derivatives.