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OPA810: bias current

Part Number: OPA810

Hi Team,

Customer wants to double check for OPA810 input bias current polarity, datasheet doesn't provide negative sign, so assume it's always one direction current? And meaning in or out? 

From below graph, it seems like bias current polarity will follow common mode voltage sign, is it correct? Thx!


  • In theory, CMOS inputs are isolated. (No DC input current is needed to make the input transistors work.)
    In practice, the bias current of CMOS inputs is leakage through the gate isolation and through the ESD protection circuits. This leakage current can flow from/to both supply rails, so it can have both polarities. Typically, the leakage is approximately symmetrical between the rails (as shown above), but there is no guarantee that the leakage in one direction isn't larger.

  • Hi Danilo,

    the input bias current of OPA810 is ultra small. Why is the direction of input bias current flow of interest?