Good day. After carefull cheking of my cirquit I have founded one error: main power supply rails are +/-5v and when I adjusting offset at input of OPamop 5v is given. It can't be cause Opamp does not have rail-to-rails input. So to avoide this can I increase 5v rail to 7v rail- there I wiil have +7V rail and -5v rail power supply. So the question is: Am I right when thinking that this adjustment won't affect OPamp except its input voltage range (with +/-5 V supply have a +/-3V input; with +7v -5V supple have a 5v -3V input range)?

Thanks for your help.

 

Yes, that is correct. Depending on the output swing of the op-amp you can change power supply rails to help increase your output swing (headroom). Of course, the easiest way is to simply use a RRO op-amp.

 

Ok, but will output signal from OpAmplifier, which is powered from unequal rails, be still refered to common GND?

The part of schematic where the problem is

 

Of course they will share the same circuit common...they would have to (unless you are doing something weird).

What are your voltages at pins 2 and ? 2.5V?

 

This crquit is used to have programmed +/-2,5V ouput. AD5220 is a digital potentometer and OpAmp+2 resistors are working as voltage follower with a 2,5V offset, which is given by 2,5v reference.

 

If you only need a 2.5V reference from the op-amp, why not use a voltage follower rather than the 'complicated' circuitry you have?

 

You misunderstood me: voltage is adjusted between +/- 2,5V