• State Resolved
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 47 subscribers
  • Views 132 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

INA333: EEG Pre-amp

Alone173
Expert 1250 points
Part Number: INA333

Tool/software:

Hello everyone.
I'm working on the project with EEG measurements device with battery power supply, so I want to make a pre-amplifier circuit before ADC input (Analog device AD7177-2).

I looked in the forum and saw that this topic:

e2e.ti.com/.../ina333-signal-amplification-with-ina333-before-feeding-to-ads1291

And I intend to use with INA333 and have some point unclearly.

1./ Does need a filter before INA333? If yes, please recommend the type of filter.

2/ The different signal of electrodes can be positive or negative in the range +/-100uV.

So, Will need config INA333 in dual-power supply mode? ( intend with same power supply of ADC, ~ +/-2.5V)

3./ The battery( 3.7V lithium or coin cell)  for power supply need buck/boost converter to make the low noise regulator of +/-2.5V, +3V3.

So, please recommend the TI's low noise buck boost and LDO, VREF ICs.

Thanks.

  • +1
    TI__Genius 12890 points

    Hello, 

    Alone173 said:
    1./ Does need a filter before INA333? If yes, please recommend the type of filter.

    Input filtering can be added if you are wanting to filter certain frequency ranges from your input signal (for example adding a low pass filter to the inputs). This is not a requirement for the INA333 to work properly and is only depending on your input signal and application needs. 

    Alone173 said:

    2/ The different signal of electrodes can be positive or negative in the range +/-100uV.

    So, Will need config INA333 in dual-power supply mode? ( intend with same power supply of ADC, ~ +/-2.5V

    What is the Vcm of the input signal? And the INA gain and Vref? Depending on what these conditions are will determine the linear operating range and if you are operating in the linear output range. 

    Alone173 said:
    So, please recommend the TI's low noise buck boost and LDO, VREF ICs.

    Our team only supports the INA and cannot comment on the LDO and Voltage reference device portfolio. Once we resolve the INA design, we can re-assign this thread to the appropriate team or you can create a new thread for this specific question. 

    Thank you!
    Regards,
    Ashley

  • 0 in reply to Ashley Kang
    Expert 1250 points

    Hello Ashley Kang,
    I send you message.
    Please help to review and confirm.
    Thank you.

  • 0 in reply to Alone173
    TI__Genius 12890 points

    Hello, 

    I did not see a message - please respond to this forum thread if you have further questions or information. 

    Thank you!
    Regards,
    Ashley

  • 0 in reply to Ashley Kang
    Expert 1250 points

    Hello Kang.
    Yes, I sent you a request for friend connection.
    Please help to check and allow for connect.

    For the current design, could you please help to review the circuit for INA333 and filter.


    Thank you.

  • 0 in reply to Alone173
    TI__Genius 12890 points

    Hello, 

    Could you clarify why you need a gain of 1001 for the INA? The INA can only go up to a gain of 1000, but even at that gain, many specs such as bandwidth and gain error are degraded. 

    Also, what is the common mode of the input signal? You mention it has a differential signal of +/- 100uV is that what is applied to both terminals? 

    What tolerance resistors are you planning on using? 

    What is the purpose of the high pass filter on the output? 

    Regards,
    Ashley