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LMC6001: Bias current ：sink or source?

user5163865
Genius 3325 points
Part Number: LMC6001

Hi,

Sorry for the basic question.

Since the input stage of the LMC6001 is a JFET, the bias current flows in only one direction, and I think it is only the sink. Is this correct?


Best Regards,
Hiroshi

  • 0
    TI__Guru 60570 points

    Hiroshi,

    Most CMOS and JFET amplifiers' input bias current, IB, is typically specified to be of either polarity because it is dominated by the net difference between two ESD diodes (from input to either rails) current leakages.  However, in order to achieve fA current level, I believe LMC6001 uses special topology resulting in actually JFET gate leakage dominating the overall IB.  Furthermore, since the input common-mode voltage range of LMC6001 reaches a negative rail, it must be an N-channel input transistor being used and for this reason it is my conclusion that the IB current would be coming out (sourcing) out of the input terminal.

  • 0 in reply to Marek Lis
    Genius 3325 points

    Marek-san,

    Thank you for your reply.
    I had thought that LMC6001 have a input stage of Pch JFET.
    I understood your great answer.

    Best Regards,

    Hiroshi