AMC1302-Q1: AMC1302-Q1 bias current in error calculation clarification

Part Number: AMC1302-Q1

Tool/software:

Hello, 

We are looking into using this iso amp for power application.  I'm doing tolerance analysis on this with the given shunt. 

Could you clarify in the datasheet does Ibias for negative and positive input is in the SAME direction or can be in opposite direction. It seem to be they are in the same direction and Ios is what defines the differential bias current. Is that correct assumption?

If they are in the same direction, how internally do they play in input offset voltage contribution?

Thank you!

  • Hi Vitaliy,

    Thank you for your questions. 

    Your assumption is correct. From our precision labs series, we provide these definitions:

    • Input bias current (I_b): current flowing into or out of the inputs of an amplifier. Can be modeled as a current source connected to each input.
    • Input offset current (I_os): mismatch between I_b flowing into the two inputs of the amplifier. 

    As we state in the data sheet, the input bias current does not generate significant voltage drop across the DC impedance of the input filter. The bias current mentioned in the data sheet is for both inputs. 

    This figure may also be helpful:

    Best regards,

    Eva