• State Resolved
  • Locked Locked
  • Replies 8 replies
  • Subscribers 47 subscribers
  • Views 1038 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.

Linux/ADS5263: ADS5263 channels crosstalk

Val Valeriy
Intellectual 430 points
Part Number: ADS5263

Tool/software: Linux

Hello folks.
I have a problem with internal crosstalk between channels in ads5263.
The situation is as follows:
when power of input signal is 0 dBm at frequency 28 MHz, decoupling between channels is about 90 dB, but when input signal power down to -30 dBm, decoupling between channels became 40 dB.

Why does this happen?

  • 0
    TI__Mastermind 49176 points
    Hi Val,

    We do not anticipate the crosstalk to vary by that amount.
    I will need to measure this data on the ADS5263EVM for your settings.
    Can you provide your register configuration?
    Additionally please provide the crosstalk spectrum for the two use cases you have listed.
  • 0 in reply to Praveen Aroul
    Intellectual 430 points

    Thank you Praveen for your reply.
    I provide you register configuration for ADS5263 (files in rar archive).
    Unfortunately i didn't have crosstalk spectrum, because we don't saved it, and now we don't have a possible do it.
    I can tell you the limits in which we changed the power of the input signal, and the frequency at which we work:

    Input frequency: 30 MHz
    Limits in which we changed the power of the input signal: -60 dBm to 0 dBm.

    As i said befor, at input power about -30 dBm or -40 dBm crosstalk between channels fell to about 40 dB.

    Help me please solve thise problem.

    Regard

    Val.ads5263.rar

  • 0 in reply to Val Valeriy
    TI__Genius 12025 points

    Hello Val,

    How are you?

    Thank you for using our ADS5263 device.

    Here we have some questions about how you set up and tested ADS5263

    in you place:

    1) Do you use ADS5263 EVM board when you are testing ADS5263 device?

    or you have your own board which has ADS5263 device on it?

    2) When you tested and measured the crosstalk from Channel to Channel,

    could you please let us know which Channel had the input power?

    and which Channel was measured and seen the crosstalk on it?

    Yes, we will do the same test with using ADS5263EVM setting very soon.

    Best regards,

    Chen

  • 0 in reply to Chen Kung
    Intellectual 430 points

    Hello Chen. Thank you for your reply.
    About your questions:
    1. Yes, we use our own board which has ADS5263 device on it.
    2. It doesn't matter which channel has input power.
    For example: when channel 1 has input power about -30 dBm or -40 dBm all othe channels have a decoupling of about 40 dB relative to the first channel.

    Best regards, 

    Val

  • 0 in reply to Val Valeriy
    TI__Genius 12025 points

    Hi Val,

    How are you?

    Thank you for replying us more detail information.

    Yes, we are running as almost the same test conditions as you mentioned:

    Input signal frequency set to 28MHz to channel 1.

    We also changed the input power about -30dBm or -40dBm for channel 1.

    However you know when we tested the ADS5263 device

    we were using our ADS5263EVM and TSW1400 capture board.

    The board input settings (using transformers) may not be the same as your own board.

    So could you please let us know the following question?

    Thank you very much!

    When you injected -30dBm input (analog signal) to Channel 1,

    how many dBFS you have captured from Channel 1's output (digital signal)?

    Could you please let us know?

    Thank can help us a lot.

    Thank you again,

    Best regards,

    Chen

  • 0 in reply to Chen Kung
    Intellectual 430 points

    Hello Chen! Thank you for your reply.
    When i injected -30 dBm signal to the 1-st channel ADC i had about 150 (digital signal) at 1's output, and it is equivalent -47 dBFS. For my 0 dBFS it is about 17,3 dBm at 30 MHz. My circuit design is the same as on a evaluation board ADS5263. I have filter fo 30 MHz bandwith and two transformers. The empedance of the channel is 50 Ohm.

    Best regards,

    Val

  • 0 in reply to Val Valeriy
    TI__Genius 12025 points

    Hi Val,

    How are you?

    Thanks for giving us more detail information.

    Yes, we were setting TI ADS5263EVM and injected 28MHz sinewave signal

    to CH1 (including very close to -47dBFS and 0dBFS) and detected any

    crosstalk happened at CH2 and CH4's digital data output.

    (Since CH3 input signal is using amplifier to drive the input pin,

    therefore we did not add it for the comparison.)

    First, you can see all the EVM board hardware settings as below:

    Secondly we injected the sinewave signal to CH1 input, so you can

    obseve the measurements (one test with CH1 output with about -47dBFS and

    one more test with CH1 output with about 0dBFS) from CH2 and CH4's output data

    which shows we can see the crosstalk between CH1 to CH2 and CH1 to CH4.

    Please also look at the following test result:

    1) When the injected CH1 signal is about -47dBFS,

    we can observe the crosstalk output data for CH2 and CH4 are shown between -110dBFS and -120dBFS.

    2) When the injected CH1 signal is about 0dBFS,

    we can observe the crosstalk output data for CH2 shown about -80dBFS

    and CH4 shown about -95dBFS (very close to what you have mentioned last time).

    This issue may be due to the trace close to the other close on the EVM.

    Because our EVM design is not targeted used for this crosstalk purpose.

    Thank you very much!

    Best regards,

    Chen