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Sallen Key filter Clarification

Category: Hardware
Product Number: LT1880

The below image is from LTC1966 datasheet.


May I know the use of RB

  • Hello,

    It looks like the additional RB on the feedback path can be used to lessen the effects of the Ibias currents flowing out of the inputs (-IN and +IN) of LT1880. The bias current flows through the resistance connected on each amplifier input which can cause a voltage shift. If the resistances at the two inputs vary, the resulting voltage shifts will also differ. This difference in voltage shifts can lead as an additional input offset error in the circuit's operation.

    Regards,
    Paul