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ADS131M08: Sampling Rate not switch from default

shishir chowdhary1
Prodigy 30 points

Part Number: ADS131M08

Hi,

I found 3 pieces of ADS131M08, which are not switch from its default Sampling Rate (4K) to desire (8K).

They all can pass all 3 stages

1. write configuration

2. read configuration

3. verify configuration

What I have to look further on this?

  

  • 0
    TI__Mastermind 25015 points

    Hi Shishir,

    welcome to our e2e forum and thank you for your interest in our ADS131M08.

    I am sorry to hear you are having difficulties with this ADC. Following a few initial questions:

    • Could you tell me your device configurations/register settings?
    • How are you determining the date rate? Are you looking at the DRDYn pin with an oscilloscope?
    • Have you provided an external clock to the device?

    Regards,

  • 0 in reply to Joachim Wuerker
    Prodigy 30 points

    Hi,

    • Could you tell me your device configurations/register settings?

      AFE_MODE        0x05, 0x10, 0x00
      AFE_CLOCK       0xFF, 0x06, 0x00
      AFE_GAIN1       0x22, 0x22, 0x00
      AFE_GAIN2       0x00, 0x00, 0x00
      AFE_CFG         0x06, 0x00, 0x00
      AFE_THRSHLD_MSB 0x00, 0x00, 0x00
      AFE_THRSHLD_LSB 0x00, 0x00, 0x00

    • How are you determining the date rate? Are you looking at the DRDYn pin with an oscilloscope?

      Yes, obtain 3906Hz

    • Have you provided an external clock to the device?

    Yes, 8 MHz

    Only 3 chips other are working fine.

     

  • 0 in reply to shishir chowdhary1
    TI__Mastermind 25015 points

    Hi Shishir,

    thanks for the additional details. I am not exactly sure what could be the issue here.

    Would you mind trying the two following things:

    • Before changing the OSR setting in the CLOCK register from the default setting, could you put the device into standby mode (send STANDBY command), then change the register setting and then wake up the device (send WAKEUP command)?
    • Replace one of the 3 non-working chips with a known-good chip to see if it is really a device issue or more a board issue.

    Regards,

  • 0 in reply to Joachim Wuerker
    Prodigy 30 points

    Hi,

    Thanks for quick reply,

    I have to try STANDBY and WAKEUP commands.

    I replace one IC, then board working fine.

    I have approx. 50 boards. 

  • 0 in reply to shishir chowdhary1
    TI__Mastermind 25015 points

    Hi Shishir,

    thanks a lot for the update. It might make sense to return some of the non-working units to us for failure analysis. However before we initiate that I would like to ask you to place the non-working IC back on the board and try it again. We call this an A-B-A test. Sometimes bad solder joints can be the cause of problems. However as you could read back the updated register settings bad solder joints are likely not the issue. But we should at least exclude this as a potential root cause.

    Regards,

  • 0 in reply to Joachim Wuerker
    TI__Mastermind 25015 points

    Hi Shishir,

    I wish you a Happy New Year.

    Have you been able to perform this A-B-A test already?
    If you want to proceed with a failure analysis please let me know so that I can loop in the respective field representative.

    Regards,