A Low Phase Noise Wide-Tuning Range Class-F VCO Based on a Dual-Mode Resonator in 65nm CMOS

A Voltage Controlled Oscillator (VCO) is a critical building block in the design of current frequency synthesizers for RF system applications. State-of-the-art operation defines that an oscillator should have the best spectral purity while consuming low amount of power for a wide tuning range. With this in mind, this work presents a low phase noise wide tuning range ClassF VCO using a dual-mode resonator. In comparison to other conventional wideband oscillators, the proposed capacitively/inductively-coupled resonator will integrate the benefits of Class-F voltage control oscillators and dual-mode switching networks to obtain simultaneous low phase noise and wide-tuning range. The proposed structure, prototyped in 65nm TSMC CMOS technology, shows a 2.14 – 4.22GHz continuous tuning range, phase noise figure-of-merit (FoM) of 192.7dB at 2.3GHz and better than 188dB across the entire operating frequency range. The oscillator consumes 15-16.4mW from a 0.6V supply and occupies an active area of 0.7mm^2 . In conclusion, the proposed resonator achieves 2- 3dB phase noise improvement while achieving 65% overall tuning range when compared to a typical class-F VCO architecture

and Applied Sciences (IJETCAS) www.iasir.net Temperature Control Circuit for Gas Sensor

Abstract: This paper presents a Temperature Control Circuit for a microhotplate based gas sensor fabricated in standard 0.35/0.18µm CMOS technology. The on-chip microhotplate provide very high temperatures (between 200ºC and 400ºC), which are necessary for the normal operation of metal oxide sensing layers. The complete temperature control circuit comprises of 10-bit A/D converter, low pass filter, two 10-bit D/A converters, two operational amplifiers and a digital controller (Vertex-IV FPGA). The required temperature is achieved by sourcing suitable amount of current to the gas sensor through a current steering 10-bit.DAC