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current measurement at nA/pA level

zhenhua lin5
Prodigy 70 points
Other Parts Discussed in Thread: ADS1216

hi all，

 I need an amplifier to measure the nA/pA level current. do u have some recommend amplifier?

thanks

  • 0
    TI__Mastermind 23050 points

    Hi Zhenhua,

    We can not make a recommendation without more information about your application. For example:

    1) What is the full scale range of current you need to measure? Will this current always be nA to pA?

    2) What are you measuring the current of? What is the system load? Are you intending to do a high-side or low-side current measurement and if high-side, what is the voltage of your system source?

    4) What supplies do you have available and what kind of output range do you need?

    The more information you can share the better we can assist you.

    Regards,

    Zak Kaye

  • 0 in reply to Zak Kaye
    Prodigy 70 points

    hi Zak，

    thank u for your reply， following is my application information

    1、the current range is 1nA~1uA

    2、what i measure is a small corrosion current of  a corrosion probe， like a primary battery，i just measure the current between the positive and the negative pole,  and  the voltage between the two poles is less than 0.5V.

    3、I would like to use a two stage amplifier and    I already choose   ADS1216  for  the AD convertion， so the max output voltage will be 2.5V

    thanks

  • 0 in reply to zhenhua lin5
    Prodigy 70 points

    hi all，

    could you  give some  recommendation about the  choice of amplifier  &the circuit

    thanks

  • 0 in reply to zhenhua lin5
    TI__Mastermind 23050 points
    Hi Zhenhua,

    I'm not very familiar with corrosion probes and am still not sure what this system looks like. Can you please share the sensor you are using and provide a datasheet if possible? Is the voltage between the poles an excitation you are providing? Is one side of this sensor referenced to ground? It sounds to me like you are using the linear polarization resistance monitoring technique, in which case you cannot measure the current between the anode and cathode of the sensor directly. Please correct me if I have misunderstood.