Intel® Agilex™ General-Purpose I/O and LVDS SERDES User Guide

ID 683780
Date 10/29/2021

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Document Table of Contents RT OCT

RT OCT with calibration is available only for configuration of input and bidirectional pins. Output pin configurations do not support RT OCT with calibration.

The RT OCT calibration circuit compares the total impedance of the I/O buffer to the external resistor connected to the RZQ pin. The impedance of the I/O buffer is continuously altered until the target impedance is achieved during OCT calibration. The targeted impedance is achieved when the impedance of I/O buffer reaches a predetermined ratio to the reference resistance.

Calibration occurs at the end of the device configuration. When the calibration circuit finds the correct impedance, the circuit powers down and stops changing the characteristics of the drivers. You may trigger re-calibration during user-mode.

Table 37.  Selectable I/O Standards for RT OCT With CalibrationThis table lists the output termination settings for calibrated OCT on different I/O standards.
I/O Standard RT OCT with Calibration (Ω)
SSTL-12 50, 60 Ω
POD12 50, 60 Ω
HSTL-12 50, 60 Ω
Differential SSTL-12 50, 60 Ω
Differential POD12 50, 60 Ω
Differential HSTL-12 50, 60 Ω