- #1
Quan24
I have a project to build a discrete operational amplifier with 1000 gain with a bandwidth from DC to 12 Mhz. I am trying to have one gain stage that sets the dominant pole at 12 Mhz and the other stages have poles at 100 Mhz while trying to keep the number of gain stages to a minimum for simplicity's sake.
Someone suggested for me to try a simple common emitter with emitter resistance. By adjusting the Re so that the zero coincide with the 1st pole, I can eliminate it and basically extends the bandwidth to its second pole.
I am having trouble finding the high frequency equation for this circuit though. All the materials I have looked at solving the high frequency without Re using the pi model. It seems placing the Re in there complicates it quite a bit.
Also since is it possible to widen the bandwidth to 100 Mhz just from this method? Are there any other tricks to lowering the Miller Effect? Please help! Also I cannot use any capacitor in my design because it has to work all the way from DC so anything that includes capacitors is out of the question.
Someone suggested for me to try a simple common emitter with emitter resistance. By adjusting the Re so that the zero coincide with the 1st pole, I can eliminate it and basically extends the bandwidth to its second pole.
I am having trouble finding the high frequency equation for this circuit though. All the materials I have looked at solving the high frequency without Re using the pi model. It seems placing the Re in there complicates it quite a bit.
Also since is it possible to widen the bandwidth to 100 Mhz just from this method? Are there any other tricks to lowering the Miller Effect? Please help! Also I cannot use any capacitor in my design because it has to work all the way from DC so anything that includes capacitors is out of the question.