ADS1192 circuit schematic

nissi7

Prodigy 165 points

Other Parts Discussed in Thread: ADS1192, ADS1292R, ADS1191, ADS1298

hi, i am designing a ads1192 based ecg sensor. can anyone help me to verify this schematic is correct?

thanks

over 9 years ago

0 nissi7 over 9 years ago

Prodigy 165 points

anyone can comment on this?

0 Brian Pisani over 9 years ago in reply to nissi7

TI__Mastermind 38745 points

Hey John,

Looks good to me.

For future reference, you may not get an answer right away on a forum question if asked on or immediately before a weekend. A good number of us are in the USA as well so please remember to consider the time difference. :-)

Regards,
Brian Pisani

0 nissi7 over 9 years ago in reply to Brian Pisani

Prodigy 165 points

Is there any guideline on the tolerances (ie. 1% or 5% etc) of passive components to be used?

0 Ryan Andrews over 9 years ago in reply to nissi7

TI__Guru 66256 points

Hi John,

I would stick to 1% resistors and 5% or 10% capacitors in the signal path. This is not a requirement that is specific to the device, just a general guideline. Also, signal chain capacitors should have an NP0/C0G temperature coefficient. The more mismatched your signal path components are, the worse your CMR will be. On the other hand, power supply decoupling capacitors can use 10% or 20%.

Best Regards,

0 nissi7 over 9 years ago in reply to Ryan Andrews

Prodigy 165 points

Is there a reference design for ADS1192/ADS1292R /ADS1191 to be used in a single lead configuration, without using the RLD signal? ie with just 2 electrode contacts to body? thank you

0 Brian Pisani over 9 years ago in reply to nissi7

TI__Mastermind 38745 points

Hey John,

There is no reference design specifically, but the strategy is relatively straightforward: simply AC couple the inputs. If you would like an example block diagram for an ECG system, look to Figure 95 on the ADS1298 datasheet. That example extends to the ADS1192/ADS1292R/ADS1191.

Brian Pisani

0 nissi7 over 9 years ago in reply to Brian Pisani

Prodigy 165 points

In the schematic in the original post, Is it ok to short Pin 31 and 32 and replace R22 and R24 with one single resistor?

0 Brian Pisani over 9 years ago in reply to nissi7

TI__Mastermind 38745 points

Hey John,

That would be fine. After giving it another review, I am concerned about the DVDD voltage. It looks like it will be the output of a buck converter meaning it is potentially noisy. You may not run into issues latching the correct values, but I could potentially see issues if the layout was such that the noisy digital supply ran too close to sensitive analog circuitry. This is not a comment on the schematic, though. If you want me to look at an eventual layout I can do that as well.

Regards,
Brian

0 nissi7 over 9 years ago in reply to Brian Pisani

Prodigy 165 points

Hi Brian, Thanks for the reply. May I know, how do I send the layout to you?

0 Brian Pisani over 9 years ago in reply to nissi7

TI__Mastermind 38745 points

Hey John,

If it is too big to put here, you can send it to pa_deltasigma_apps@ti.com. I can only look at gerbers or Altium files FYI.

Brian Pisani

0 nissi7 over 9 years ago in reply to Brian Pisani

Prodigy 165 points

Hi Brian,
Thank you. Sent you email with my design files.

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ADS1192 circuit schematic