OPA192: How to show current noise (pA/sqrt(Hz)) for a current source by using Noise Analysis?

James Ye1

Part Number: OPA192
Other Parts Discussed in Thread: TINA-TI,

I built a TINA-TI Howland Current Pump then did a "Noise Analysis" for "output", I expected the result to show pA/sqrt(Hz), but the result shows v/sqrt (Hz) instead. Is this just a graphing error or is it really showing output voltage noise and I need to convert it to current noise?

OPA192_CCS - autosave 19-10-11 18_48.TSC

over 5 years ago

0 James Ye1 over 5 years ago

Prodigy 50 points

update: please use this .TSC file - the previous one was incomplete.

OPA192_CCS.TSC

0 kai klaas69 over 5 years ago in reply to James Ye1

Guru 140200 points

Hi James,

just add an output voltage pin (VF1) in parallel to Rload and you will see that it is indeed the noise current which is displayed:

Kai

0 Tamara M Alani over 5 years ago

TI__Genius 10850 points

Hi James,

Kai is correct.

-Tamara

0 James Ye1 over 5 years ago in reply to Tamara M Alani

Prodigy 50 points

Kai and Tamara:

even though the Y axis is displaying V / sqrt(Hz). It is in effect A / sqrt(Hz). in another word, TINA-TI is not smart enough to know the output is current and not voltage in Noise Analysis.

Please confirm my understanding is correct.

Thanks,

James

0 Tamara M Alani over 5 years ago in reply to James Ye1

TI__Genius 10850 points

Thanks, James. I'll make note of this feedback.

0 kai klaas69 over 5 years ago in reply to James Ye1

Guru 140200 points

Hi James,

but TINA-TI is smart enough to do all these powerful and time saving simulations for you. And that for free...

Kai

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OPA192: How to show current noise (pA/sqrt(Hz)) for a current source by using Noise Analysis?