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LOG114: Offset drift and input bias current

Part Number: LOG114

Hi team,

My customer considers employing LOG114 for their product and provided some questions as follows.

  1. Datasheet shows Vos drift is ±15uV/℃(typ).
    It measns ±1σ(68%) of device-to-device offset drift distribution should be less than ±15uV/℃
    Is this understanding correct?
  2. As for input bias current, datasheet simply shows "±5pA(typ)" and "doubles every 10℃".
    Is there any other information regarding input bias current such as distribution histogram?

I'm looking forward to hearing back from you.

Best regards,

Shota Mago

  • Hi Shota,

    Typical specs usually represent a mean ±1σ value for a parameter. If the variation in that parameter takes on a Gaussian distribution, then ±1σ would represent ~68% of the distribution. Without a histogram for the drift spec, it's not certain that 68% of devices would fall into that specification, it's only possible to say that that represents a ±1σ value.

    No histogram is available for the input bias current specification.

  • Hi Alex-san

    Thanks for your quick reply.

    Does drift variation of LOG114 takes Gaussian distribution?

    If not, how does datasheet specify TYP value?

    In terms of input bias current, is there anything else data?

    I think this parameter is critical for trans-impedance amplifier application.

    Best regards,

    Shota Mago

  • Hi team,

    Do you have any update on this?

    Best regards,

    Shtoa Mago

  • Hello Shota,

    The LOG114 datasheet does not provide any offset drift distribution information for the voltage offset. However, the A1 through A5 Op amps are JFET op amps that are not trimmed for a specific offset drift characteristic so a population of LOG114 devices are likely to exhibit a normal distribution.

    The input bias current IB is typically ±5 pA at TA = +25°C. It approximately doubles for every 10°C increase in temperature from TMIN to TMAX.

    Regards, Thomas

    Precision Amplifiers Applications Engineering