ADS1292R: ADS1292R Data retrieval issues

Anakshi Rajput

Part Number: ADS1292R

Tool/software:

Hi,

In this Ads1292R I have tested test signals which is giving perfectly square wave but when i am giving any other wave whether it is sine wave or ECG it is very noisy and i am facing one more issue now i am not able to detect device Id suddenly after some days it stopped detecting device id.

5 months ago

0 Ryan Andrews 4 months ago

TI__Guru 66466 points

Hi Anakshi,

Thank you for your post. Can you recheck all power supplies and VCAPx voltages? Do you see the DRDYn signal toggling after power-on reset procedure is completed?

You can find other helpful debug FAQs on our ADS129x BIOFAQ page on E2E!

Regards,

Ryan

0 Anakshi Rajput 4 months ago

Prodigy 40 points

Hello Ryan,

Thanks for your reply device Id problem is solved and I have found one thing when I m using pc charger that time I am getting clean Ecg but when I am not charging the pc I am getting noisy waveform so most probably it is a ground issue but in my layout both digital and analog gnd are seperate and my input to this board for Ecg is through fluke analyzer I am not using RLD also I made it buffer. I am attaching images with pc charging and without charging. Sampling rate -125samples/sec, Gain-12.

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0 Ryan Andrews 4 months ago in reply to Anakshi Rajput

TI__Guru 66466 points

Hi Anakshi,

The RLD is required to establish a known common-mode voltage for the input signals from the body/simulator. This is needed to ensure the PGA in front of each ADC channel is operating properly. If RLD is not used, then it is recommended to AC-couple the inputs and use a high impedance network to bias each input to mid-supply or RLDOUT.

I'm not sure why charging your PC would make a difference, perhaps there is a grounding issue as you mentioned. The analog and digital grounds should be tied together close to the IC, or you can make them one solid ground plane as well.

Regards,

Ryan

0 Anakshi Rajput 4 months ago in reply to Ryan Andrews

Prodigy 40 points

Hello Ryan,

Thanks for sharing this in my ckt I am using anti aliasing low pass filter input side and then for respiration ckt as given in datasheet I have changed one thing I have tied p side with VDD/2 but not with n -side Do you think this can be a problem.

0 Ryan Andrews 4 months ago in reply to Anakshi Rajput

TI__Guru 66466 points

Yes, both respiration inputs require biasing to mid-supply because they are AC-coupled.

Regards,

Ryan

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ADS1292R: ADS1292R Data retrieval issues