OPA817: Drift of bias current

Taito Takemura

Intellectual 2060 points

Part Number: OPA817

Hi experts,

Could you please tell me the bias current drift (Vs=±5V) of OPA817DTKR?

The bias current of the FET input op amp grows exponentially with temperature, so I'm concerned about its drift. Is it possible for you to tell me the bias current drift in units of A/℃?

Thank you for your help.

Regards,

Taito Takemura

8 months ago

0 Ignacio Vazquez Lam1 8 months ago

TI__Genius 9470 points

Hi Taito,

Although we don't provide a spec for bias current drift, we do have an input bias current vs temperature graph (Figure 7-29) that highlights this shift. We also give a max value of input bias current across temperatures.

Best Regards,

Ignacio

0 Taito Takemura 8 months ago in reply to Ignacio Vazquez Lam1

TI__Intellectual 2060 points

Hi Ignacio,

Is it possible to calculate the drift of input bias current from the original data of Fig7-29?

Regards,

Taito Takemura

0 Ignacio Vazquez Lam1 8 months ago in reply to Taito Takemura

TI__Genius 9470 points

Hi Taito,

Although this isn't a spec in the datasheet and will vary as this is a rough estimate, we can do a rough calculation using the points from the figure I highlighted.

(-40 - 2)pA / (85 + 40)°C = -.336pA/°C

This will vary lot to lot and is not a guaranteed spec but can be used a rough guide based on the ib vs temperature graph mentioned above.

Best Regards,

Ignacio

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OPA817: Drift of bias current