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Nulling the offset

Discussion in 'Electronic Design' started by john, Apr 18, 2007.

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  1. john

    john Guest

    Hello,

    I am using texas instrument's part number INA2133U and OPA 131 to
    build the constant current source. The following link will take you
    to
    the circuit and data sheet ( page 13, figure 16). The inverting input
    of the amplifier is grounded.


    http://focus.ti.com/lit/ds/symlink/ina2133.pdf


    I tested the circuit for Leakage current and with zero input
    voltage ,
    load resistor of value 100kohm, R = 50kohm and rail voltages of +/-
    15volts, I am getting current in the range of 1 to 10 micro amp,
    which
    is undesirable for my application. The questions are as follows


    1. Do I need offset trimming like the data sheet discussed it on page
    number 9?
    2. Is there any other way to stop this leakage current?


    The desirable leakage current range is less than 1 micro amp.


    Please advice!


    John
     
  2. Winfield

    Winfield Guest

    Please don't double post, we saw your first post.
     
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