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OPA4188 for myoeletric processing

Prodigy 70 points

Replies: 1

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Hi

I was wondering if the OPA4188 would give a good performance for a signal processing. Im doing a band pass filtering, from 5Hz to 520Hz and was thinking on using that opamp... is a good choice??

best regards

1 Reply

  • The OPA4188 is optimized for great dc performance (very low offset and offset drift) but it’s ac performance is just ok for your needs. Since the application is a band pass filter, you don’t really need good dc performance (the dc offset is essentially filtered out by the high pass part of your band pass circuit).

    I think for your application you should focus on the amplifiers with the best ac characteristics. The Gain Bandwidth Product (GBW) is the most important. Assuming For best performance the gain bandwidth product should be a decade higher than the bandwidth you are trying to achieve (assuming Gain = 1). So, for your circuit you should look for GBW = 5MHz or higher. You may want to use a software tool like filter pro to help with the design. Filter pro will tell you the required GBW needed for your circuit. Filter pro is a free tool from TI (see link below).  Also, I would simulate the result in Tina Spice as well.  Tina can uncover other issues such as common mode and output swing limitations.

    http://e2e.ti.com/support/amplifiers/precision_amplifiers/w/design_notes/3076.filterpro-v3-1

    Other ac characteristics that may be important are Slew Rate, and noise. The OPA4172 and OPA1652 are some options of devices that have great ac characteristics. The OPA1611 has very good ac characteristics.

    Art

    Art Kay, Applications Manager Precision ADC

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