Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Document Table of Contents OCT Calibration

Stratix V GX and GS devices contain calibration circuits that calibrate the OCT resistors and analog portions of the transceiver blocks to ensure that the functionality is independent of process, voltage, and temperature (PVT) variation. GT devices do not have calibration support.

The calibration block internally generates a constant reference voltage, independent of PVT variation. The calibration block uses the internal reference voltage and external reference resistor to generate constant reference currents.

Note: You must connect a separate 1.8 kΩ (maximum tolerance ±1%) external resistor on each RREF pin to ground. To ensure the calibration block operates properly, the RREF resistor connection on the board must be free from external noise.