A 0.74 mW, linear-in-dB, constant bandwidth, variable gain amplifier based on zero-pole repositioning technique

Abstract

A zero-pole repositioning based variable gain amplifier is presented in this paper. The operational principle of this unique structure is discussed, its most important formulas are derived and its outstanding performance is verified by simulation in TSMC 0.18 µm standard CMOS technology. Owing to the cutting-edge structure, the proposed circuit demonstrates a very low power consumption of 0.74 mW and a wide tuning range of 83 dB. The proposed structure benefits from linear-in-dB and constant bandwidth specifications. The linear-in-dB gain range of structure is about 70 dB. The structure draws about 413 µA from 1.8 V power supply and regarding this low power consumption, it shows a lower and upper 3-dB cutoff frequencies of 8 Hz and 8.1 MHz, respectively. Process and temperature variation analysis of the circuit is also investigated through Monte Carlo and corner case analysis in order to verify the well-robustness of the structure. The transient sinusoidal response analysis is also done to verify the proposed VGA's stability.