Author Topic: Cmod A7 driving some DACs  (Read 1216 times)

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Offline ezalysTopic starter

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Cmod A7 driving some DACs
« on: August 17, 2021, 11:42:24 pm »
Hey everyone, I'm curious about using the Cmod A7 to drive a pair of DAC3174s. I'm curious  about

  • Which pins can be used as LVDS pairs?
  • Of those pairs, what kind of DDR datarate can I hit?
  • How will the signal integrity look after cramming those fast signals through those 0.1" headers :P

Best wishes,
Evan
 

Offline asmi

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Re: Cmod A7 driving some DACs
« Reply #1 on: August 18, 2021, 01:17:14 am »
I'm afraid you can't use that board to drive LVDS because 7 series FPGA's IO bank needs to be powered by 2.5 V in order to output LVDS (inputs are possible with any Vccio if you don't use on-chip termination and instead use external resistors), and as far as I remember Cmod A7 is a 3.3V-only system. Answering questions 2 and 3 seems pointless in light of that, but in general all differential pairs of 7 series FPGAs are identical and can reach the same data rate using SERDES (950 Mbps for speed grade 1, 1250 Mbps for SG 2 and 3). As for SI, I think your main issue will be a lack of length matching (both within diff pair and between lanes) and not necessarily connector itself.
« Last Edit: August 18, 2021, 01:20:52 pm by asmi »
 
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