Designing of High Speed Floating Gate Differential Ring RLC VCO with Error-Tracking MISO Filter for Low Noise Applications

This paper presents a new architecture of VCO based on floating gate differential ring architecture along with a comparative analysis of relaxation floating gate differential ring VCO and RC floating gate differential ring VCO along with an an approach of analytical designing of Multiple Input Single Output (MISO) filter based on the analysis of J. Satan sup. The main advantage of Multiple Input Single Output filter over Single Input Multiple Output is its ability to avoid interference. Though MISO filter is available in literature but our approach in this paper lies in the idea to use it in high speed transmitter with VCO. All the oscillators are designed using 180 nm technology. We use 1.8 V power supply for simulation. We analyze both linear VCO circuits and non-linear VCO circuits for measuring noise performance of our proposed VCO architecture. Frequency range of 1 GHz-5 GHz is used for noise analysis. The proposed architecture of floating gate differential ring VCO gives very good performance for increased frequency range. Due to the use of 5 stage ring structure in the proposed VCO architecture, the stability factor is increased with reduced noise. This new VCO will fulfill the demand of high speed transmitter for its high speed data transmission. The value of noise in the RF frequency range of 1 GHz-5 GHz comes out to be (6.02*10 (-10)) dBc/Hz. This noise value is comparatively low in comparison to other VCO architectures. We have also proved that with increase of capacitance value in VCO circuit, the power dissipation will be more. The stability factor is decreased with increase of the value of capacitance and inductance. The proposed floating gate RLC VCO will give promising result with low power, low noise and high stability factor. Our proposed VCO will give 244% better result in terms of noise as compared with the two stage RC differential ring VCO. Though the expected value of measured noise level is in the negative range but we prefer a very low offset due to the increased frequency range. With increase in frequency range for the high speed VCO, it is expected that the noise value should be more. To overcome this disadvantage and to make the noise level of our proposed VCO circuit low so that it will work as an ideal VCO, it is necessary to have its noise level to near about zero. The proposed VCO meets the demand of high speed circuit. CADENCE Virtuoso is used for simulation purpose.