Arria V: VOD values for LVDS i/o

[Altera_Forum]

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 far end. Please note, that I am not asking for the xcvrs. Rather the LVDS i/os.  Anyone know where I can get this information? I cannot find it in the datasheet as well.  TIA. Best regards, Sanjay

[Altera_Forum]

As far as I know, there are no such setting. User only required to set differential at the RX side.  

 Also the 0 1 2 seems like the drive strength for normal GPIO output....

[Altera_Forum]

Hi Sanjay, 

 The VOD will large be dependent on the board setup. It is recommended for your to run IBIS or Hspice simulation to determine the VOD and VID in your setup.

[Altera_Forum]

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.

[Altera_Forum]

You can find the links to IBIS and Hspice download page at here: 

 https://www.altera.com/support/support-resources/support-centers/signal-power-integrity.html

[Altera_Forum]

The Arria V LVDS VOD specification is from 0.247 to 0.6V. You should expect your VOD within this range. You can refer to Table 19. Differential I/O Standard Specifications for Arria V Devices in Arria V device datasheet for further details.