Active biquad tunable filter design

This paper presents the technique of single differential stage op-amp which is used for the active biquad filter design with the inclusion of buffers at the output of op-amp. This procedure provides the advantage of low power and low area requirement with reduction of propagation delay. The buffer circuit proffers the tunability of the filter by modulating the transconductance of the output buffer. This approach has been established to design a second order active biquad filter. The two biquad high pass and low pass sections are used to design a fourth order band pass and band stop filter with 0.18 µm CMOS process technology which consumes significantly less power than conventional approaches.