Design of a Highly Linear Voltage Differencing Transconductance Amplifier Using Source Degeneration

This paper presents a highly linear voltage differencing transconductance amplifier (VDTA) utilizing a source degeneration technique to enhance input linearity while maintaining wide bandwidth. The incorporation of source degeneration within both transconductance stages of the proposed VDTA significantly improves the linear input range and suppresses harmonic distortion through controlled local negative feedback. The proposed VDTA is implemented using 180nm CMOS technology and the circuit operates at 0.9V with a bias current of 50A. The proposed VDTA achieves an asymmetrical linear input range from -310 mV to +321 mV (631 mV pp ) at 1% transconductance error bound, extending to -410 mV to +419 mV (829 mV pp ) at 5% error threshold and exhibits low THD of about 0.76%, provides a transconductance gain of 1mS and attains a 3dB bandwidth of 478MHz. A thorough performance evaluation is conducted through DC, AC, transient, and Monte Carlo analyses. The design exhibits excellent robustness under PVT variations and demonstrates electronic tunability. The proposed VDTA thus offers a practical and efficient solution for linear, high frequency analog signal processing applications. To validate the practical applicability of the proposed architecture, a voltage-mode universal MISO biquad filter has also been implemented and verified through SPICE simulations.