What transceiver PMA blocks are used in the Intel® Arria® 10 device internal serial loopback path?

Description

The Intel® Arria® 10 transceiver internal serial loopback path includes the Variable Gain Amplifier (VGA) and Decision Feedback Equalizer (DFE) when enabled. It does not include the TX VOD, TX Pre-emphasis, RX Continuous Time Linear Equalizer (CTLE), and RX DC Gain PMA blocks.

Resolution

Adjusting TX VOD, TX Pre-emphasis, RX CTLE, and RX DC Gain will not affect the signal seen by the CDR when using internal serial loopback. Adjusting RX VGA and RX DFE when enabled will affect the signal seen by the CDR.