0.5 V Universal Filter and Quadrature Oscillator Based on Multiple-Input DDTA

Abstract

This paper presents a universal voltage-mode filter and quadrature oscillator based on low-voltage multiple-input differential difference transconductance amplifier (MI-DDTA). Unlike the previous published DDTAs, that utilize the bulk-driven (BD) multiple-input MOS transistor technique (MI-MOST) in the differential pair of the first stage only, the proposed DDTA, for the first time, utilize the BD MI-MOST in the second stage of the DDTA. This results in capability of providing more arithmetic operations without additional current branches or power dissipation. Hence, simplify the topology of the filter and oscillator applications, by decreasing the count of active blocks. The voltage-mode filter offers high-input and low-output impedances, and both non-inverting and inverting versions of five types of transfer functions, namely low-pass, high-pass, band-pass, band-stop, and all-pass characteristics. The oscillator offers three-phase of quadrature signals, and orthogonal control of the condition and frequency of oscillations. The circuit was designed in Cadence environment using 180 nm CMOS TSMC technology. The voltage supply is 0.5 V and the power consumption of the filter is 472 nW. The simulation results are in accordance with theory and confirm the performance of the proposed circuit.