Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

Arria V: VOD values for LVDS i/o

Hello, I can see in the Arria V handbook that we can have 3 settings for LVDS TX I/O. 0, 1 and 2. I am wondering what these would correspond to on the board assuming 100ohm termination at the...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

Sanjay,

I think you are referring to the Programmable Differential Output Voltage (VOD) that is in the Quartus assignment. It is actually a pre-emphasis that increases the amplitude of the high-frequency component of the output signal. So you will see a boost at the at the initial part of the signal to be slightly higher, so that when it reaches the Rx side, it will still have a nice eye opening. You need to test out on a simulator with IBIS or Hspice to know what setting would give what eye opening on the Rx.