10-27-2014 06:10 AM
I'm sat here reading through UG381. Our application interfaces a Spartan 6 LX45 to an Analogue Devices ADC.
We therefore have 1.8V LVDS input, but also need 1.8V LVCMOS for the ADCs SPI.
If I set VCCO to 1.8V, table 1-5 states we can get LVCMOS1V8 operation both input and output. However I can't see anything on 1.8V LVDS input (only the 2.5V and 3.3V variants).
My question is: Are there any restrictions on VCCAUX (which from Table 1-6, I imaging should also be connected to 1.8V).
The other banks are either set to 2.5V or 3.3V LVCMOS I/O only so VCCAUX shouldn't be a problem for them right?
10-27-2014 06:15 AM
From DS162 Table 2, it looks like 2.5V minimum for VCCAUX.
As such how should we go about getting a suitable mid rail bias voltage for LVDS1.8V?