OPA227: About Vos.

Leo Ma

Expert 4196 points

Part Number: OPA227

Hi Expert,

Have a nice day! I have question need your professional support:

For OPA227, it’s Vos is about 10uV:

So, If I connect V+ and V- to ground as this schematic, then the Vout should be 100*Vos=1mV. Is the equation right?

But when use TINA to simulate, the result is just 12.72Uv.

Could you help to explain why?

A diagram of a circuitAI-generated content may be incorrect.

Thanks!

Best Regards,

Leo Ma

3 months ago

+1 Clemens Ladisch 3 months ago

Guru 321020 points

A typical value is not guaranteed, and a model cannot simulate a random distribution. See figure 6-10:

With a Vos of up to ±200 µV, the output can be up to ±20 mV.

0 Leo Ma 3 months ago in reply to Clemens Ladisch

TI__Expert 4196 points

Thanks Clemens,

So, does this mean in the TINA simulation I showed, the Vos of OPA227 is just 127nV?

Regards,

Leo Ma

0 Chris Featherstone 3 months ago in reply to Leo Ma

TI__Mastermind 28205 points

Hi Leo,

I have downloaded our reference design as shown below and I am getting the same offset voltage as described in the product datasheet. I have attached my simulation for reference to the bottom of this post.

The reference design comes from this link:

Reference Design

sboc188d.TSC

Best Regards,

Chris Featherstone

0 Leo Ma 3 months ago in reply to Chris Featherstone

TI__Expert 4196 points

Thanks Chris!

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OPA227: About Vos.