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ADS1292: Problem with analog bypass capacitor

Margarida Reis
Prodigy 10 points
Part Number: ADS1292

Hello,

I am trying to interface with the ADS1292R via SPI, however I believe I have a problem with the voltages required to properly interact with the device.

I am powering it with unipolar supplies with AVDD = DVDD = 3.3V. I also setup the circuit recommended on the datasheet for single supply operation with all the mentioned capacitors. I read on the forum that the voltage on VCAP1 should be 1.2V and on VCAP2 it should be AVDD + 1.8V. In fact, I have 1.2V at VCAP1, however I am measuring around 2.6V at VCAP2, which is not close to what I was expecting.

Could this be the reason why the device is not responding? I used a logic analyzer to see that whenever I pull the START line HIGH there are no changes in the DRDY line which leads me to believe that the device isn't properly working.

Do you have any idea of what I might be doing wrong?

Thank you,

Margarida

  • 0
    TI__Guru 66406 points

    Hello Margarida,

    Welcome to our forum!

    This could be an indication that the device has been damaged or has some other problem. Has this happened on more than one device? Can you communicate with the device at all, such as reading/writing registers?

    Another thing I would confirm is that the reference voltage is present (VREFP) and that the clock (CLK) is active. If you are using the internal oscillator, you can probe the clock signal on the CLK pin if the CLK_EN bit (CONFIG2[3]) is enabled.

    Best Regards,