Excess noise in OpAmp Simulations

Hi adamvs ,

I've tried testing the Voltage Noise on my end. (The way it was tested when the model is being built)

I attached it here for you to see and simulate and relate to the datasheet.

I noticed that it is not as expected from the datasheet, but, this is probably the way it was asked to be modeled.

If you do have questions on the results of your model simulation, you can always communicate with the FAE in charge of the part for them to verify if this is really a model issue. If it is, then, we will be expecting a request from them to assess this issue.

Nonetheless, models are created and verified by the FAE to assess if it really represents the actual part performance.AD8655_Input_Voltage_Noise.zip

Best Regards,

Earl

Hi Earl,

Thanks for the reply. If i understand you correctly, you agree the sim doesn't match what you would expect from the datasheet?

I really am not familiar with the relationships between the various parties you mention. How can I find the FAE for a product?

NB: I did test this with a second OpAmp, and neither matched the expectations form the datasheet, though some agree better than others.

Hi adamvs ,

I can't really say on my part if the model behavior matches or not, the voltage noise could have been tested differently than the way I was testing it. (Which is a straightforward approach).

You can always communicate with our ADI contact center or if you do have someone already in communication with ADI then you can ask an FAE to assist you.

For now, what I can do to help you here is verify our noise simulation if it really does not follow the datasheet. With that said, please give me time to do so.

Best Regards,

Earl

Hello EarlJohn and adamvs,

Jumping in really quick here. It really looks like the noise behavior of the model does not match the actual behavior of the part. I have done some simulations on my own and it looks like the broadband noise of the model is higher compared to the actual broadband noise of the part:




I think the noise behavior of the model should be fixed. I can initiate a request for it to be fixed.

Best regards, 
Paul

Hi  ,

Thanks for verifying this concern, please let me know if you've already made a rquest for this, I'd gladly take it for me to fix it.

Best Regards,

Earl

Hello EarlJohn,

I have already initiated the request through the LTSpice Service Desk. Thank you very much.

Best regards,
Paul

Hi  ,

I assigned it to myself. I'll give you an update outside EZone on the progress of updating this model.

Best Regards,

Earl