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TL3016: What is the differential input impedance of the TL3016?

koumei okahara
Prodigy 50 points
Part Number: TL3016

Tool/software:

Hello,

I am using a TL3016.

If the voltage difference between the + and - inputs is large, the input current will be large.

Can you tell me what the differential impedance of the inputs is?

Best regards,

  • 0
    TI__Mastermind 25990 points

    Okahara-san

    Thanks for your post.  The input bias current is fairly flat at 6uA (typ) over the input operating voltage range of VCC- + 1.5V and VCC - 1.5V.

    In general, comparators provide input bias current so designers know the appropriate resistance to the inputs to meet their system accuracy requirements.

    Bias current drop across resistance essentially looks like input offset voltage.

    Chuck

  • 0 in reply to Chuck Sins
    Prodigy 50 points

    Hello Chuck

    Thank you for your reply.

    I also thought the bias current would be about 6uA as stated in the datasheet, but when I actually input 3.5V to the + input and 1.75V to the - input, the input current on the + input side becomes large at about 15uA. (When the voltage on the - input is higher, it is equivalent to the bias current stated in the datasheet.)

    Is there any reason why the current increases due to the input voltage difference like this?

  • +1 in reply to koumei okahara
    TI__Mastermind 25990 points

    Okahara-san

    I am going to take this offline since we are actively working on a next generation version and are trying to understand use cases.  Forest and our designers should be able to help answer based on their knowledge of the input structure.  When you receive my email, please reply and include your operating voltage and exact setup (schematic would be preferred).  Thanks, Chuck