Hello,
I am working on a redesign, I want a variable gain amplifier that has the same phase with different gain. In the old system it was done using an opamp and a digital potentiometer, noninverting amplifier. But because I'm changing the gain, I am affecting the bandwidth of the circuit, so the phase could be different. Also the digital potentiometer has capacitance, which would make it an RC filter and when the resistance is changed the cut-off frequency of the RC filter also changes and would affect the phase.
So I wanted to replace this circuit with the VCA824, but I wanted to know if the phase is the same at different gain.
Or are my assumptions wrong and it is possible to make a variable gain amplifier out of an opamp without any change in phase?
Best regards,
Sang