Square-Root-Domain current-mode electronically tunable universal filter

In this study, current-mode square-root-domain (SRD) electronically-tunable universal filter is proposed. The proposed circuit has one input and five outputs and can realize low-pass (LP), band-pass (BP) high-pass (HP) allpass (AP) and notch (N) responses without any changes in the circuit topology. In order to get variable quality factor value, the feedback is applied to the filter. Only MOS transistors and grounded capacitors are required to realize the filter circuit. The natural frequency and quality factor of the LP, BP, HP, AP and N can be electronically tuned by changing DC current sources. Time and frequency domain simulations are performed using PSPICE program for universal filter to verify the theory and to show the performance of them. For this purpose, the filter is simulated by using TSMC 0.35 µm Level 3 CMOS process parameters.