Re: cmfb
Actually there are two techniques to realize differential outputs from single ended inputs. One thing is to get an amplifier and a unity gain amplifier in series. There will be delay issues in this case. You can use it if you are not doing filter design or using wideband frequencies. Or else there is also a parallel technique. Here, we feedforward the common mode level. Please refer to the attachment for some insight. I have implemented both the things with success in industry and in college. I am sure that it will work for you.