IOBUFDS_DIFF_OUT and IOBUFDS_DIFF_OUT_XP5 - IOBUFDS_DIFF_OUT and IOBUFDS_DIFF_OUT_XP5 - UG861

Spartan UltraScale+ FPGAs SelectIO Resources User Guide (UG861)

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

The following figure shows the IOBUFDS_DIFF_OUT (HP and HD I/O banks only) differential input/output buffer primitive with complementary outputs (O and OB). A logic High on the T pin disables the output buffers. When the output buffers are 3-stated (T = High), the input buffer and any on-die receiver termination (uncalibrated or DCI) are ON. When the output buffer is not 3-stated (T = Low), any on-die receiver termination (uncalibrated or DCI) is disabled. TM and TS must be connected to the same input from the interconnect logic for this primitive to have the expected behavior that is specific to the UltraScale architecture.

Figure 1. Differential Input/Output Buffer Primitive with Complementary Outputs for the Input Buffer (IOBUFDS_DIFF_OUT)

The IOBUFDS_DIFF_OUT_XP5 is the same functionally but must be used when the IOB exists in an XP5IO I/O bank.