Low-Voltage Mixed-Mode Analog Filter Using Multiple-Input Multiple-Output Operational Transconductance Amplifiers

Abstract

This paper presents a novel mixed-mode, low-power, 1 V analog filter that uses multiple-input multiple-output operational transconductance amplifiers (MIMO-OTAs). This filter uses four OTAs, two grounded capacitors, and one grounded resistor and offers four modes, namely voltage, current, transconductance, and transimpedance modes. Each mode of operation provides non-inverting and inverting low-pass, high-pass, band-pass, band-stop, and all-pass filter transfer functions (10 transfer functions). Thus, in four operating modes, the designed filter offers 40 transfer functions, which is the full capability of a mixed universal filter. The natural frequency of all filter functions can be electronically controlled. To obtain the multi-input OTA, the multiple-input bulk-driven MOS transistor (MIBD-MOST) technique is used. This technique can reduce the number of MOS input differential pairs and the supply voltage. The active mixed-mode filter was simulated using a CMOS TSMC $0.18 \mu \text{m}$ process in the Cadence Virtuoso ADE Suite. The simulation results confirm the performance of the proposed filter.

Keywords

• Active filter
• mixed-mode filter
• operational transconductance amplifier
• low-power circuit
• analog circuit