OPA197: Input offset drift - maximum 2.5uV/C but distribution shows no statistic?

HAREL LEVY

Part Number: OPA197
Other Parts Discussed in Thread: OPA196

Tool/software:

Hi everyone,

If you could look at the datasheet of OPA197 you can see that the maximum value for the input offset drift is 2.5uV/C but figure 4 shows the statistical distribution of the input offset drift values and there is no statistical value for this maximum drift. Is this a mistake?

2 months ago

0 Chris Featherstone 2 months ago

TI__Mastermind 26005 points

Hi Harel,

I collected the drift data for this device. The 2.5 uV/C spec is a 6 sigma number with the average at 0.5uV/C. These specs are derived from the distribution data I collected which is in figure 4.

Let me know if you have any other questions or need clarification.

Best Regards,

Chris Featherstone

0 HAREL LEVY 2 months ago in reply to Chris Featherstone

Prodigy 250 points

Thank you Chris,

I need to do an RSS error in PPM for the thermal drift of a circuit consists of this op-amp configured as a differential amplifier with a gain of 3.7/0.02. what value of offset drift should I take? As I understand from you the probability to get a 2.5uV/C op-amp is very very low ( 6 sigma ), will a 3 sigma value be more appropriate?

0 Chris Featherstone 2 months ago in reply to HAREL LEVY

TI__Mastermind 26005 points

Hi Harel,

6 sigma is a conservative number and statistically you could see 1 out of 506.8 million units with drift at that level. For a 3 sigma event you could see 1 out of every 370.4 units with a drift at the 3 sigma drift value. See below.

Best Regards,
Chris Featherstone

0 HAREL LEVY 1 month ago in reply to Chris Featherstone

Prodigy 250 points

Thank you so much for this information,

can you tell me what is the 3 sigma value for the offset drift of the OPA197 & OPA196?

0 Chris Featherstone 1 month ago in reply to HAREL LEVY

TI__Mastermind 26005 points

Hi Harel,

I am currently looking into this and will let you know shortly.

Best Regards,

Chris Featherstone

0 Chris Featherstone 1 month ago in reply to HAREL LEVY

TI__Mastermind 26005 points

Hi Harel,

1.25uV/C would be the 3 sigma number for OPA197. OPA196 we do not provide any Vos stats in the PDS or distributions and only a typical spec for drift.

Best Regards,
Chris Featherstone

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OPA197: Input offset drift - maximum 2.5uV/C but distribution shows no statistic?