• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 46 subscribers
  • Views 1409 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADC12DJ3200: JESD204b line rate caculation

user5242214
Prodigy 20 points
Part Number: ADC12DJ3200

I want to know the actual line rate of JMODE 1. in JMODE 1, sampling rate is 6.4 GSPS. According to the data formats in page 66 of datasheet, can I caculate line rate as below:

6.4 GSPS/80*64bit*10/8=6.4 Gbps.

But in traditional way to caculate line rate, the result is 6.4 GSPS*16bit*10/2/16=8 Gsps.

Which one is correct?

Thank you!

  • 0
    TI__Mastermind 44560 points

    Hi user

    The first calculation is correct.

    The second 'traditional' method assumes there are 16 bits generated for every ADC sample. This method works for converters where every sample value is padded up to 16 bits long before formatting and transmission. This is the case for many 14b and all 16b JESD204B ADCs. For this 12b ADC using this method is very inefficient. Instead of padding every sample to be 16b or 2 octets long, we pad the end of every data frame with 4 bits so the frame is 8 octets long. This padding adds much less overhead.

    The easiest way to find the line rate for the ADC12DJ3200 is to find the value in the R column (Fbit/Fclk) in Table 18. For the JMODE1 case you mention, at 6.4 GSPS the input clock rate is 3.2 GHz. Since R=2 the line rate is 3.2*2 = 6.4 Gbps.

    Best regards,

    Jim B

  • 0 in reply to Jim Brinkhurst1
    Prodigy 20 points

    Thank you  very much! It's very helpful.