Arria 10 GX Transceiver Signal Integrity Development Kit Board

Dear,

I have one "Arria 10 GX Transceiver Signal Integrity Development Kit" board.

When running BTS (Board Test System) to check high speed signal of Arria 10 transceiver, I found that the eye height of 2.4mm SMA "J31" and "J33" is about 60mV lower than "J68" and "J72".

The VOD setting value is 31. The test pattern is PRBS7.

Then, I checked all the 2.4mm SMA high speed signal, I found that all the 2.4mm SMA connected to bank 1G are about 60mV lower than 2.4mm SMA which are connected to bank 1F in eye diagram.

What is the reason that leads to the different performance between bank 1G and bank 1F?

1. SMA to bank 1G has longer PCB routing than SAM to bank 1F?

2. Bank 1G has 4 channel transceiver running, while bank 1F only has 2 channel. So, bank 1G has more current loading than bank 1F. Thus cause lower lower eye height ?

3. Other reason, ? Please help.

Thank you.

Brs,

Leon