Narrow Results

Nonequilibrium transport of charged carriers in a two-dimensional electron gas is summarized from an experimental point of view. The transport regime in which the electron–electron interactions are enhanced at high bias leads to a range of striking effects in a two-dimensional electron gas. This regime of transport is quite different than the ballistic transport in which particles propagate coherently with no intercarrier energy transfer and the diffusive transport in which the momentum of the electron system is lost with the involvement of the phonons. Quite a few hydrodynamic phenomena observed in classical gasses have the electrical analogs in the current flow. When intercarrier scattering events dominate the transport, the momentum sharing via narrow angle scattering among the hot and cold electrons lead to negative resistance and electron pumping which can be viewed as the analog of the Bernoulli–Venturi effect observed classical gasses. The recent experimental findings and the background work in the field are reviewed.

This paper presents a scalable low voltage CMOS folded-cascode quadrature voltage controlled oscillator (QVCO) design for radio-frequency (RF) applications using the TSMC 0.18 μm 6M1P CMOS process technology. The simulated startup behavior of this proposed QVCO topology indicates that, the QVCO is free from bi-modal oscillation (frequency ambiguity). The QVCO provided extended voltage swing with the supply voltage scalable in the range of 1.8 V to 0.75 V. The QVCO operates in the frequency range of 4 GHz to 3 GHz (corresponding to supply voltage scaling in the range of 1.8 V to 0.75 V) with around 11.7% tuning range and low quadrature error. The QVCO had a power consumption under 10 mW within the specified supply voltage scaling range. Phase noise simulations using the Monte Carlo analysis provide an approximate phase noise estimate of ≈ -150 dBc/Hz at an offset of 600 KHz from the center frequency (@3.7 GHz) for operation using the 1.8 V supply voltage, using moderate inductor-Q values. Monte Carlo simulations were also carried out to determine the effects of the process, voltage and temperature variations.

The object of this paper is to introduce a new CMOS differential input single output (DISO) transconductor (realizable from eight MOSFETs operating in saturation) and a dual input dual output (DIDO) transconductor (realizable with 16 MOSFETs operating in saturation) and their applications in realizing grounded/ floating, positive/ negative, electronically controllable resistors and inductors. The workability of all the prepositions has been demostrated by SPICE simulations using TSMC 0.18$\mu$ m CMOS technology parameters. The paper, thus, adds a number of useful electronically-controllable circuits to the existing repertoire of CMOS analog circuits for signal processing.