AD597: Gain adjustment

Document created by analog-archivist Employee on Feb 23, 2016
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Please can you assist with the following.  With regards to the gain, is there
some setting/gain resistor which has to be included? If so between which
terminals?

 

No.
It  is not possible to lower the gain of the AD597 by connecting a potential
divider between Vout and FB.
If you connect a resistor R2 between Vout (pin7) and FB (pin6) and connect a
resistor R3 from FB to ground , the gain will be given by the equation:
Vout/Vin = [ ( RFB/Rin ) x ( 1+ R2/R3 ) + ( R2/Rin ) ]

It is not possible to choose values for R2 and R3 which will make the term ( 1
+ R2/R3 ) less than unity. Therefore you cannot reduce the gain lower than it’s
nominal value of 245.

The only thing you can do is to connect Vout to RFB to give a gain of 245 and
then use a potential divider as an attenuator (i.e. not in the feedback loop)
to reduce the gain by a factor of 2.57.

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