So I need to do range switching on an input signal that is multiplied to high gains using a op-amp cascade to increase bandwidth. I need four ranges.
One way I thought to do it is to just put four op-amps with the same gain and tap them off with switches, so I can select the output of OPA1,2,3,4.
The other way is to use many more switches (I guess 4 per op amp, which is not THAT bad, and this way I don't need four OPA (the gain bandwidth product requirement is satisfied with 2 op amps really).
Have you guys seen either of these methods used in actual designs? I am not worried about the op-amp noise in particular. Using four equal gain op-amps and tapping them off seems like the best solution even though I only need two.
I need at least two op-amps, unless you have a 20 GHZ op amp.