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DDC264: Would this application work?

Tom Stern
Prodigy 10 points
Part Number: DDC264

I have a voltage source (1V or lower) connected to a very high impedance path, in the order of GOhms. I would like to integrate current over time to get a reading. Current is in the nA scale.

What would be the ideal connectivity to an input in that case. My circuit can be been ac VCC + resistor connected to it. Normally goes to GND, however I would like to measure current so perhaps should be connected directly to the input or otherwise?

Thanks!

  • 0
    TI__Mastermind 19815 points

    Hi

    Do you have any idea/estimate what might be the current lower bound and upper bound? Because whether the device can integrate&acquire&convert the current properly depending on the input current range as well as the selected Range and Integration time.

    Please take a look of datasheet page 6 -

    and page 24 and 26.

    Thanks,

  • +1
    TI__Expert 4680 points

    Hi Tom,

    Not sure I understand the "My circuit can be been ac VCC + resistor connected to it" but yeah, if you connect the 1G, that is usually connected to GND, now directly to the input of the DDC, you should be able to measure the current no problem.

    Regards,

    Edu

  • 0 in reply to Eduardo Bartolome
    Prodigy 10 points

    Sorry for not being too clear. In order not to go into details of my actual circuit, it can be simplified and viewed as a voltage source + series resistance to ground. This model is 'good enough' (engineering!) in representing the expected behavior of the circuit, for my needs anyway. Thanks!