• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 47 subscribers
  • Views 3399 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Best Instrumentation Amplifier for high impedance source

robert bible
Prodigy 115 points
Other Parts Discussed in Thread: INA121

I need to design a couple  of differential input pre- amplifiers for a high impedance electrochemistry potential type of measurement. The target impedances of my circuitry are 10 megOhm and 100 megOhm or greater (both).. the differential signal range is about 1 volt.. The frequency of the  signals is DC to 4 Khz.  This is a battery operated system with 20v battery.   The output is going to a National instruments DAQ with 24 bit sampling at 10Khz (1 meg Ohm input impedance).  Other features I would like are over-voltage protection, and ESD input protection,, obviously I will need to filter RFI .

Which IA should I choose and any recommendations on the circuitry would be nice. This is a new realm for me and I am not experienced with the tricks of dealing with high impedance signals.  

Thanks, Robert

  • 0
    TI__Guru 69261 points

    obert,

    The highest input impedance instrumentation amplifier for Vsupply of 20V is our INA121 with input impedance in Tera-ohm  range - see below.  

    It has also sufficient bandwidth for your application up to a gain of 1,000.

    INA121 has internal over-voltage as well as ESD protection - see below.