Carbon Nanotube Field Effect Transistors Based Low THD and Noise-Immune Double Stage Differential Amplifier for Nanoelectronics

Double Stage Differential Amplifier comprises many advantages by operating differential inputs. It provides excellent immunity to external noise which is certainly a flawless advantage for low-power devices and also reduces Low-Order Harmonics (LOH). This paper presents the design of a double stage differential amplifier using Carbon Nanotube Field Effect Transistors (CNTFETs). The key approach of the proposed design is to reduce the Total Harmonic Distortion (THD), Low-Order Harmonics (LOH), output delay and to achieve a high transconductance gain, gm. The paper also carries the significant comparisons between conventional differential amplifier and the proposed design. Both circuits have been simulated by using HSPICE model of CNTFET. The optimized threshold voltage is 0.309V and given bias is IV only. The Fast Fourier Transform (FFT) and Fourier analysis also shows an outstanding result compared to the conventional one. Moreover, the output voltage is closely zero at common-mode operation which yields a very high Common-Mode Rejection Ratio (CMRR). From the analysis in both common-mode and differential-mode inputs the proposed design was proven to be robustly noise-immune.