A constant Q-factor notch filter using voltage difference transconductance amplifier

Abstract

This paper demonstrates a novel design of Notch filter circuit availing Voltage Difference Transconductance Amplifier (VDTA) active element. The proposed circuit utilizes two VDTA blocks, two capacitors without the use of resistor and operates in voltage-mode. The devised Notch filter circuit uses 150 µA biasing current and operates with ±0.9 V supply voltage. The transconductance value of this element is electronically controllable/tunable with the bias currents. The proposed filter operates at low voltage and is widely used in optical communication systems, biomedical applications and audio applications. The circuit is implemented in the Cadence Virtuoso tool of the gpdk 180 nm CMOS process.