Agilex™ 7 General-Purpose I/O User Guide: F-Series and I-Series

ID 683780
Date 10/07/2024
Public
Document Table of Contents

2.4.1.1. Single-Ended I/O Standards On-Chip Termination

Serial (RS) and parallel (RT) OCT provides I/O impedance matching and termination capabilities. OCT maintains signal quality, saves board space, and reduces external component costs.

The OCT calibration circuit uses the impedance of the external resistor that is connected to the RZQ pin as reference. During calibration, the circuit continuously alters the impedance of the I/O buffer until the impedance reaches a predetermined ratio to the reference resistance.

Table 9.  OCT Schemes Supported in F-Series and I-Series Devices
Direction OCT Scheme
Output RS OCT with calibration
RS OCT without calibration
Input RT OCT with calibration
Bidirectional Dynamic RS and RT OCT