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TLV3691: Max Ibias within a smaller temperature range

Part Number: TLV3691

Hello,

The maximum Ibias shown in the data sheet is 20 nA across the full temperature range.  In my application the allowable temperature range is -40C to 85C.  I would like to find out if there is any data indicating the maximum Ibias within this smaller range or if there is any (conservative or otherwise) way to extrapolate a value.

Thanks,

Narek

  • Narek,

    Since the IB current in CMOS input diff pair comes from the reverse-biased leakage of the ESD protection diodes, its magnitude doubles with every 10 deg C increase in temperature.  Thus, you may calculate back the max IB at 85C by recognizing that it is 40 deg C lower than 125C max IB of 20nA.  

    Therefore, max IB(@85C)=20nA/2^(40C/10C)=20nA/16=1.25nA;  the typical graph of IB vs Temp is shown below:

  • Hello Narek,

    CMOS input device bias current doubles every 10°C, though here can be deviations at the lower and upper temperatures.

    To get a worst case at 85°C, just extrapolate back from the 125°C maximum.

    125°C = 20na
    115°C = 10na
    105°C = 5na
    95°C = 2.5na
    85°C = 1.25na <-
  • Thank you Marek and Paul for your quick response. Extremely helpful and educational.

    Narek