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Likely pole locations for AD713, and reasons to use AD713 as unity gain amplifier?

Question asked by ksathyadev on Oct 4, 2016
Latest reply on Oct 5, 2016 by krisf

Hi,

 

Two questions here:

 

A) I was thinking where the poles of an Op amp IC are likely to be. Example I check the datasheet of an Op amp AD713, and a straight line is shown for the frequency range 30Hz to 10MHz (page 7 of datasheet, Rev F, 2011). Is it proof enough to assume that first pole < 30Hz and second pole > 10MHz?

 

B) I found AD713 used as an unity gain amplifier in a design, and was checking why it would have been used. Do these reasons hold good, and what else could have determined the choice:
i) That it has a good gain margin (gain approx ~15dB below zero dB when phase is -180 Deg)
ii) Appears to have a very huge phase margin (phase is 50 degrees when gain is 0 db, which make phase margin as 50 degrees difference -180 degrees, ie 230 Degrees)

Are my points i) and ii) above correct? Any more reason that AD713 would have been used. Frequency of operation is less than 1kHz. 

 

Regards
-Sathyadev

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