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ADS54J60: VOD Minimum Spec

Sepeedah Zadeh
Expert 3620 points

Part Number: ADS54J60

Hello team, 

Customer is trying to understand minimum output amplitude VOD on ADS54J60. Datasheet only calls out the typical value, can you please help out? Info is needed to make sure after signal drop across traces it is still within supported range of the FPGA. 

Thanks,

Sepeedah

  • 0
    TI__Guru* 91947 points

    Sepeedah,

    We are looking into this.

    Regards,

    Jim

  • 0 in reply to jim s
    TI__Guru* 91947 points

    Sepeedah,

    I have not heard back from the design team yet. We have connected the customer EVM to the capture board using an 8 inch extender board. The total trace length was over 14 inches and never had an issue with the serdes outputs. I have never had a customer ask for this either. How long is their trace? What type of board material do they plan on using?

    Regards,

    Jim  

  • 0 in reply to jim s
    TI__Expert 3620 points

    Understand Jim. Please let me know when you can.

    Customer FPGA has minimum input voltage of 150mV and so channel voltage margin will be calculated by Vmargin = ADC JESD204B MIN output voltage / FPGA MIN input voltage.

    JESD204B standard has specified the MIN output voltage as 360mV, which means, in general, we have voltage margin of 7.6 dB.

    I think this number is used to roughly calculate allowable attenuation across channel, which covers 3rd harmonics of maximum fundamental frequency of Serial lane.

    The expectation is that ADS54J60 supports higher minimum output voltage than JESD204B standard and by knowing this value customer can understand which parameters to play with such as trace length and board material and what is the limit.

    Does this line up with your understanding of how to factor in losses and make sure the signal that reaches the FPGA is still within acceptable range?

  • 0 in reply to Sepeedah Zadeh
    TI__Guru* 91947 points

    Sepeedah,

    I still have not heard back from the design team. I will ping them again today.

    Regards,

    Jim  

  • 0
    TI__Guru* 91947 points

    Sepeedah,

    I got this today from the design team:

    "There may be loose test-limit on VOD. It is not a part of datasheet spec".

    I have a feeling this is all they are going to provide us with.

    Regards,

    Jim