TINA - INA111, How to simulate noise behavior (differential mode and common mode).

Jamaal_Charles

Other Parts Discussed in Thread: INA111

Hello,

I am trying to use TINA to simulate noise behavior of the INA111 (differential mode and common mode), but I can't figure out how to do it? Is it possible?

I need to see the noise rejection performance. I tried to use a DC V-source to simulate a 0~20mV signal (DC), and then added an sinusoid 0~5mV V-source to simulate added differential noise. But that approach didn't work.

Any suggestions?

Thank you!

over 11 years ago

0 John Miller - Sensing over 11 years ago

TI__Mastermind 40295 points

Jamaal,

What simulation mode are you trying to use to capture the noise behavior, AC or transient?

Regards,
John

0 Jamaal_Charles over 11 years ago in reply to John Miller - Sensing

Genius 3245 points

Hi John,

AC.

Thanks

0 John Miller - Sensing over 11 years ago in reply to Jamaal_Charles

TI__Mastermind 40295 points

Jamaal,

Another question: is it the actual noise you want to see, or the common-mode rejection?

Regards,
John

0 Jamaal_Charles over 11 years ago in reply to John Miller - Sensing

Genius 3245 points

Hi John,

Both, actuallly. I want to know how to use TINA to simulate differential mode and common mode noise rejection performance of our circuit.

Also, how to inject differential mode or common mode noise (stimulus) into the simulating circuit.

Thanks,

0 John Miller - Sensing over 11 years ago in reply to Jamaal_Charles

TI__Mastermind 40295 points

JC,

I'm still a ilttle unclear on what you want to do.
The rejection of external, input common-mode noise should be covered by the device's CMRR.
A differential noise source will be subject to the device's nominal differential gain.

Attached to this thread is a modified version of the reference circuit you can find at the device product page:
http://www.ti.com/product/ina111/sboc137

The existing circuit is set up for diff gain. A noise source applied to the same connections as VIN will result in diff noise out. A second circuit has been added for input common-mode. Running an AC sim will give you the corrresponding diff & common-mode gains.

Please ley me know if this helps, or if you have any other questions.
Regards,
John

sboc137b[1]_mod.TSC

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TINA - INA111, How to simulate noise behavior (differential mode and common mode).