High Frequency and High Linearity Transconductance Capacitor Filter

To improve the frequency and linearity of filter,a new transconductance operational amplifier was presented,in which cross-coupled differential structure was used to improve DC transmission characteristics of the transconductance input stage and extend the linear input voltage range.To stabilize output common-mode level and increase dynamic range of the filter,a CMFB circuit was proposed,along with gain adjustment method for each branch.Theoretical analysis was made,which was verified with simulation.Results showed that the Gm-C filter had a cutoff frequency of 159.6 MHz,a transition bandwidth greater than 45 dB and a dynamic range of 64 dB.