A Real-Time Electronically Tunable All-MOS Universal Biquadratic Voltage-Mode Filter

Abstract

— In this paper, an electronically tunable universal biquadratic voltage-mode filter that is based only on MOS transistors is proposed. Configuration of the proposed filter is simple and there is no need to use component matching. Since the proposed filter contains only MOS transistors, it is very suitable for implementation in system-on-chip (SoC) applications. The cutoff frequency of the lowpass (LP) and highpass (HP) filters as well as the center frequency and the bandwidth of the bandpass (BP) and bandstop (BS) filters can be controlled either in a continuous range or in a discrete manner by means of a digital control word. Besides, the filter type can be changed during the real time by an appropriate code. Operation of all the filtering functions are verified by simulation using the Berkeley predictive-technology models (BPTM) of the 130 nm complementary metal-oxide semiconductor (CMOS) technology with power-supply voltage, VDD, of 1.2 V. The proposed filter is analyzed quantitatively, and the effects of the total-harmonic distortion (THD), noise, process, voltage and temperature (PVT) variations are also investigated. The average power consumption of the LP, HP, BP, BS, and allpass (AP) filters are found to be 30, 118, 74, 118, and 30 (all in µW). The price paid for all these advantages is more sensitivity to process variations for the lowpass filter.