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ADS1299-4: NO output

Eric(Dongguan) Zhu
Intellectual 1450 points
Part Number: ADS1299-4
Other Parts Discussed in Thread: ADS1299

hi team,

the customer's sch. is attached.

The DRDY script itself has an external pull-up. Under normal circumstances, it should be always low, but now it is low. The BIASINV output should be 2.5V normally, but the output is close to 0.

please give some suggestions.

  • 0
    TI__Mastermind 19815 points

    Hi,

    Correction, First of all, /DRDY should remain HIGH whenever data is not transmitting from slave device(e.g. ADS1299 in this case) to host(e.g. customer's uController or processor or FPGA), /DRDY should be HIGH.

    Only when the data is ready to be transmitted out from the slave device, the /DRDY would go LOW - e.g. please refer to ADS1299 datasheet page 34,35,39.

    So, would you please clarify what you mean by "Under normal circumstances, it should be always low, but now it is low." ?

    BIASINV output depends on the BIASREF_INT setting and the (AVDD+AVSS)/2 and whether customer close any of the BIASxP and/or BIASxN  mux/switches. So, it's not always and not necessary to be 2.5V. Please refer to ADS1299 page 33 Figure 38.

    Thanks

  • 0 in reply to ChienChun Yang
    TI__Intellectual 1450 points

    thanks your reply.

    please help review customer's schematic.

  • 0 in reply to Eric(Dongguan) Zhu
    TI__Mastermind 19815 points

    Hi,

    I provided my feedback above after reviewed, and Some of those, customer need to verify in their software/firmware register settings.

    Please,

    "So, would you please clarify what you mean by "Under normal circumstances, it should be always low, but now it is low." ?

    Thanks.