THS4551: THS4551

Mikhail Isagulov

Part Number: THS4551
Other Parts Discussed in Thread: ADS127L11

Hello,

I am designing a board with THS4551 in a few configurations: FDA with -3dB around 200kHz, MFB Bessel stages, ADC (ADS127L11) driver.

It was very-very helpful and easy to base my simulations on the TINA simulation files that the datasheet points on.

The TINA model from July 2016 is mentioned in this thread. I was almost sure the model in the downloaded files is from June 2016.

Checking, I found that the loop gain simulation file uses June/2016 model and the other files use July/2016 model.

Exchanging the models (the parts) in the schematics, I got different results above 200 – 220MHz.

Comparing the scripts (the models) by text editor, I found they are slightly different.

Which of them you recommend to use?

Sincerely,

Mikhail

over 4 years ago

0 Michael Steffes over 4 years ago

Guru 48395 points

Yes Mikhail, I also noticed that back in 2019 while I was testing the updated model in an MFB filter. I had put some effort into capturing the highly resonant open loop Zo for the 2016 model in the designer sims. That was softened quite a lot in the model update (I am suspecting only RC in the Zo model, I use RLC to capture the 2nd order shape). I would use the 2016 model frankly if you have that direct C feedback of the MFB - I also started adding an inside the loop small R to help this before tapping off the feedback elements.

6014.THS4551 model concerns in testing new vs old one in an MFB design.docx

+1 Mikhail Isagulov over 4 years ago in reply to Michael Steffes

Prodigy 120 points

Hello, Michael,

Thank you very much for the immediate answer.

All the simulation files, I use, are from 2016.

May you, please, try to check what are the differences between the June/2016 and July/2016 model. Which of them is closer to the reality?

Thanks in advance,

Michael

+1 Michael Steffes over 4 years ago in reply to Mikhail Isagulov

Guru 48395 points

We were making small model changes back then, I have the July model at the release model - use that one.

The 2019 update was going to a internal template that I think converges better, but also loses this Zol accuracy it seems.

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THS4551: THS4551