TITLE:
Realization of Resistorless Voltage Mode Universal Filter and Quadrature Oscillator Employing DDTAs with CMOS 180 nm Technology at 0.2 V
AUTHORS:
Ghanshyam Singh
KEYWORDS:
CMOS Technology, Differential Difference Transconductance Amplifier (DDTA), Voltage Mode Universal Filter, Quadrature Oscillator
JOURNAL NAME:
Circuits and Systems,
Vol.17 No.6,
June
30,
2026
ABSTRACT: This paper presents a low-supply-voltage CMOS realization of a Differential Difference Transconductance Amplifier (DDTA) operating at a supply voltage of 0.2 V. The proposed DDTA achieves high operational capability while consuming ultra-low power of 356.66 nW, making it suitable for low-frequency biomedical and sensor applications. The proposed configuration employs two DDTAs and two grounded capacitors to implement a voltage-mode universal filter and a quadrature oscillator. These circuits are applicable to signal generation, audio and image processing, instrumentation, biomedical systems, and sensor interfaces. The universal filter exhibits high input impedance and allows electronic tuning of the natural frequency in the range of a few hundred hertz. The band-pass filter demonstrates a total harmonic distortion (THD) of 0.46% for a 100 mVpp input signal at a frequency of 83.97 Hz. With minor modifications to the universal filter structure, a quadrature oscillator is obtained in which both the condition of oscillation and the oscillation frequency are electronically controllable. The THD corresponding to an oscillation frequency of 68.23 Hz is approximately 1.16%. The proposed circuits are designed and simulated using 180 nm CMOS technology in PSPICE. Simulation results confirm the effectiveness and performance of the proposed universal configuration.