CMOSインバータを用いたアクティブRCポリフェーズフィルタの設計

摘要

We have investigated a possibility of using simple CMOS inverters as amplifiers in wide band active-RC polyphase filters (A-RCPF). Simulation study was conducted on a nomalized 5-stage A-RCPF with a passband(stopband) of 0.1 to 10 [rad/S] to find necessary voltage gain(transconductance) of OPA(OTA). A design procedure of A-RCPF using CMOS inverters is proposed. Assuming 0.18 μm CMOS process, a three-stage CMOS-inverter-based A-RCPF with passband(stopband) from 1 MHz to 100 MHz was designed following the design procedure. The simulation result shows good frequency response. The A-RCPF operates from 1.8 V of power supply voltage and consumes 5 mA for each CMOS inverter (60 mA, in total). A three-stage A-RCPF with passband of 5 kHz to 500 kHz was designed and realized by uslng Standard discrete CMOS logic TC4069 for the purpose of verification of the procedure. The measured result of the bread board supports the design procedure. The simulation and B/B results supported the possibility of wide band A-RCPF using CMOS inverters.