Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Document Table of Contents Transmitter Analog Settings

The transmitter analog setting capability improves signal integrity. These analog settings can be dynamically reconfigured without powering down the device using the PMA analog registers within the reconfiguration controller on GX devices only. Dynamic reconfiguration of the PMA settings can be done concurrently and independently per channel

Programmable Output Differential Voltage

You can program the differential output voltage to handle different trace lengths, various backplanes, and receiver requirements.

Figure 17. VOD (Differential) Signal Level

Programmable Pre-Emphasis

Pre-emphasis can maximize the data eye margin at the far-end receiver. The programmable pre-emphasis module in each transmit buffer boosts high frequencies in the transmit data signal, to compensate for attenuation in the transmission media.

Stratix V GX channels provide three pre-emphasis taps: pre-tap (16 settings), first post-tap (32 settings), and second post-tap (16 settings). The pre-tap sets the pre-emphasis on the data bit before the transition. The first post-tap and second post-tap set the pre-emphasis on the transition bit and the following bit, respectively. The pre-tap and second post-tap also provide inversion control, shown by negative values.

The Stratix V GT channels have two pre-emphasis taps: pre-tap and post-tap. Each tap has 32 settings.