Hi,
I am designing an amplifier in inverting configuration with variable gain.
But when switching the gain of by changing the value of the feedback resistor, the CL 3dB bandwidth also will change since the GBW is fixed. So how could I fixed the CL bandwidth?? acceptable variation will be +/- 20% over corners.
Thank you in advance!
Thanks for your answers!
Other than this, is there any simple way to do it? how about switching different size of caps in parallel with fb res to limit the bandwidth?
There are only a few active filters that lend themselves to variable gain and fixed bandwidth. Usually one must choose a feedforward , or wide band flat amp with variable gain independant of the filter as any negative feedback of the filter that controls gain will also control bandwidth.
**broken link removed**
Frequency response is within 0.25 dB of flat between 30 Hz and 15 kHz. The gain can be adjusted between unity and +15 dB.