OBUFDS - 2024.1 English

UltraScale Architecture Libraries Guide (UG974)

Document ID
UG974
Release Date
2024-05-30
Version
2024.1 English

Primitive: Differential Output Buffer

  • PRIMITIVE_GROUP: I/O
  • PRIMITIVE_SUBGROUP: OUTPUT_BUFFER
  • Families: UltraScale, UltraScale+

Introduction

The OBUFDS is a differential output buffer primitive.

I/O attributes that do not impact the logic function of the component, such as IOSTANDARD, DRIVE, and SLEW, should be supplied to the top-level port via an appropriate property. For details on applying such properties to the associated port, see the Vivado Design Suite Properties Reference Guide (UG912).

Logic Table

Inputs Outputs
I O OB
0 0 1
1 1 0

Port Descriptions

Port Direction Width Function
I Input 1 Buffer input
O Output 1 Diff_p output. Connect directly to a top-level port in the design.
OB Output 1 Diff_n output. Connect directly to a top-level port in the design.

Design Entry Method

Instantiation Yes
Inference No
IP and IP Integrator Catalog No

VHDL Instantiation Template

Unless they already exist, copy the following two statements and paste them before the entity declaration.
Library UNISIM;
use UNISIM.vcomponents.all;

-- OBUFDS: Differential Output Buffer
--         UltraScale
-- Xilinx HDL Language Template, version 2024.1

OBUFDS_inst : OBUFDS
port map (
   O => O,   -- 1-bit output: Diff_p output (connect directly to top-level port)
   OB => OB, -- 1-bit output: Diff_n output (connect directly to top-level port)
   I => I    -- 1-bit input: Buffer input
);

-- End of OBUFDS_inst instantiation

Verilog Instantiation Template


// OBUFDS: Differential Output Buffer
//         UltraScale
// Xilinx HDL Language Template, version 2024.1

OBUFDS OBUFDS_inst (
   .O(O),   // 1-bit output: Diff_p output (connect directly to top-level port)
   .OB(OB), // 1-bit output: Diff_n output (connect directly to top-level port)
   .I(I)    // 1-bit input: Buffer input
);

// End of OBUFDS_inst instantiation

Related Information

  • UltraScale Architecture SelectIO Resources User Guide (UG571)
  • Vivado Design Suite Properties Reference Guide (UG912)