Article different result's between ADIsimPE and Diff Amp Calculator!!!

Original Question: different result's between ADIsimPE and Diff Amp Calculator!!! by BRADDIS

hi every one.

I have some issue's with this soft ware's...

I am designing a single ended to differential converter with AD4940.

the Diff Amp Calculator shows that Band Width of circuit is 24Mhz

but with  ADIsimPE B.W is 72 Mhz ...

what is wrong?!

which one i must trust??


Verified Answer: RE: different result's between ADIsimPE and Diff Amp Calculator!!! by ezadminThis question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin
Question: RE: different result's between ADIsimPE and Diff Amp Calculator!!! by BRADDIS

Can you help me please?


Question: RE: different result's between ADIsimPE and Diff Amp Calculator!!! by JinoL

Hi Brad,

ADA4940 has a different dynamic performances for Small Signals and Large Signals. Typical -3dB BW for SS is 240 MHz while for LS it's 24 MHz. This difference in dynamic performance of the amplifier is the reason why you are getting those results. 

SPICE cannot do Large Signal plots accurately. Now, if you would look at the Diff Amp Calculator, the tool assumes that the Amplifier would amplify signals to the level compatible with the ADC and that's the reason why it shows max -3dB BW 24 MHz.

So for your question, trust the Diff Amp Calculator.

Regards,

Jino

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