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INA333 ECG low supply 1.8V problems

tomasz radomski
Prodigy 100 points
Other Parts Discussed in Thread: INA333

Hi, 

i would like to use INA333 with single supply voltage 1.8V  in my ECG project.

i have a few questions: 

- what are the potential problems with ECG input amplifiers like INA333 and low single supply like 1.8V or below

- will RLD amplifier with the same supply be able to drive RLD (right led drive) electrode to cancel DC offset from signal electrodes, what should be reference voltage for it? middle of 1.8V, 0.9V? 

- what is the maximum difference in potential between RLD electrode  end other electrodes? 

  Thanks in advance for help.

BR

Tom 

  • 0
    Guru 21975 points

    Tom,

    The best bias point would be at 0.9V, mid-supply. This would allow the maximum possible input and output voltage range for the INA333.

    The maximum difference voltage between RLD and other electrodes will vary considerably with environmental conditions and electrode resistance. Please understand that we at TI do not have much experience in this area. We know our ICs. Engineers who work in the ECG area invest careers developing these circuits and there is much to be learned, evolved and refined to perfect this input circuitry. I suspect that companies that have spent years evolving their circuitry and methods may tend to guard what they know.

    There are many postings on this forum (mostly appear to be students) who are attempting to design this type of circuitry. You are welcome to search and explore these postings. I also invite others outside TI to comment on this question.

    Regards, Bruce

  • 0 in reply to Bruce Trump

    Sir , I would like to design an ECG using INA 333 can you please give me the guidelines for designing it ?