No output on ADS8319

Michael Ratterman

Other Parts Discussed in Thread: ADS8319

Hello,

I am having trouble getting an output on SDO pin of my ADS8319 in 3 wire mode without busy indicator.

I attached my analyzer waveforms and I think I am performing the timing right per the datasheet. Could I be missing something?

Thanks for your help

over 12 years ago

0 Harsha Munikoti over 12 years ago

TI__Expert 5705 points

Hi Michael,

Are you not getting any data or are you getting incorrect data? Could you please post a plot of the ADC's SDO line? Also, please make sure you are connecting the IO grounds of the ADC (BDGND) and the SPI host together.

Regards,

Harsha

0 Michael Ratterman over 12 years ago in reply to Harsha Munikoti

Prodigy 110 points

Harsha,

I am getting incorrect data on SDO, The SDI label in my pic is actually the SDI of my host connected to SDO of the ADS8319. The SDI of the ADS8319 is connected to VDD. Both are connected to ground.

Thanks

Mike

0 Harsha Munikoti over 12 years ago in reply to Michael Ratterman

TI__Expert 5705 points

Hi Mike,

Sorry for the delay. I wonder if something might be loading the ADC output. Note that ADC output should be floating while CONVST is high and driven after the falling edge of CONVST, which does not seem to be the case in your plot. Could you please post a schematic of your circuit?

Also, have you observed any disruptions in the ADC's power supply that might be causing it to become unresponsive?

Thanks,
Harsha

0 Michael Ratterman over 11 years ago in reply to Harsha Munikoti

Prodigy 110 points

Harsha,

I have not noticed any disruptions, attached is the schematic.

Thanks

Mike

0 Harsha Munikoti over 11 years ago in reply to Michael Ratterman

TI__Expert 5705 points

Hi Michael,

I see that you are using 3.3V for +VA. The ADS8319 needs +VA to be between 4.5V and 5.5V to function. Please fix this and let me know if your results don't change.

Best Regards,

Harsha

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No output on ADS8319