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ADS7871: ADS7871 suddenly fails to output DOUT

Part Number: ADS7871

Hi team,

A customer doese not have company email so I help him to post this issue.

this issue is ADS7871 suddenly fails to output DOUT while in use.
Occasionally, ADC values could not be sent to MCU.

Phenomenon: 1) Normal progression of all 8CHs in ADS7871
2) All 8CHs output to zero with Random.
Analysis: 1)CLK, DIN appears to be normal.
2) The DOUT also sends a signal, but it does not appear to be a normal signal.

Figure 1. Normal DOUT

Figure 2. Abnormal DOUT

Can you share your suggestion?

Thanks.
Regards,

Frank

  • Frank,

    1. Normally, when looking at digital signals it is best if you can capture SCLK, DIN, and DOUT.  For future posts, please add those signals.
    2. On a positive note, your DOUT signal looks clean (i.e. no overshoot, ringing, noise).  So, I doubt this is a data integrity issue. 
    3. Since all the channels give poor (near zero) results, at one time I think you may have an intermittent connection.  
      1. Is this one prototype that is being tested?  If so double check the soldering.
      2. Check the reference input.  Is that signal stable?
      3. Other pins like RESET, and OSC ENABLE could impact operation if the signal on these pins is intermittent.
    4. If you check the connections as above and think they are stable you should provide a schematic.  

    I hope this is helpful to you.

    Best regards,

    Art