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How to enable on-chip 100 ohm resistor for LVDS input.

Altera_Forum
Honored Contributor II
‎03-05-2011 05:43 PM
2,134 Views

How to enable on-chip 100 ohm resistor for LVDS input. 

I am using Stratix IV EP4sGX530 . 

My tool is Quatus II 10.0 

In datasheet stx4_siv51008_lvds,we can find these words . 

Row I/Os support true LVDS input with 100-ohm differential input termination (OCT RD), 

SO I don't place any external 100ohm resistor in my board. 

But How can I enable these on-chip 100 ohm resistor . 

Some one said if I choose LVDS IO standard in assignment editor, these resistor will be enabled automatically. 

But when I download my FPGA . 

All LVDS signal connected with ROW I/O meet serious singal integrity problem . 

Because Column I/O don't support on-chip 100 ohm resistor , I added external resistor .It work well . 

I think I don't really enable these on-chip 100 ohm resistor . 

Can anyone tell me how to enable it . 

Thanks.
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Altera_Forum
Honored Contributor II
‎03-05-2011 08:17 PM
1,278 Views

Select Input Termination/Differential/Yes for the respective pin, either in the assignment editor or the pin planner.

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