Iet Circuits Devices & Systems 

About: Iet Circuits Devices & Systems is an academic journal published by Institution of Engineering and Technology. The journal publishes majorly in the area(s): CMOS & Amplifier. It has an ISSN identifier of 1751-858X. It is also open access. Over the lifetime, 1216 publications have been published receiving 12287 citations. The journal is also known as: IET circuits, devices and systems & Circuits, devices & systems.

Xampling: Analog to digital at sub-Nyquist rates

Abstract: The authors present a sub-Nyquist analog-to-digital converter of wideband inputs. The circuit realises the recently proposed modulated wideband converter, which is a flexible platform for sampling signals according to their actual bandwidth occupation. The theoretical work enables, for example, a sub-Nyquist wideband communication receiver, which has no prior information on the transmitter carrier positions. The present design supports input signals with 2 GHz Nyquist rate and 120 MHz spectrum occupancy, with arbitrary transmission frequencies. The sampling rate is as low as 280 MHz. To the best of the authors' knowledge, this is the first reported hardware that performs sub-Nyquist sampling and reconstruction of wideband signals. The authors describe the various circuit design considerations, with an emphasis on the non-ordinary challenges the converter introduces: mixing a signal with a multiple set of sinusoids, rather than a single local oscillator, and generation of highly transient periodic waveforms, with transient intervals on the order of the Nyquist rate. Hardware experiments validate the design and demonstrate sub-Nyquist sampling and signal reconstruction.

Design of energy-efficient and robust ternary circuits for nanotechnology

Abstract: Novel high-performance ternary circuits for nanotechnology are presented here. Each of these carbon nanotube field-effect transistor (CNFET)-based circuits implements all the possible kinds of ternary logic, including negative, positive and standard ternary logics, in one structure. The proposed designs have good driving capability and large noise margins and are robust. These circuits are designed based on the unique properties of CNFETs, such as the capability of setting the desired threshold voltage by changing the diameters of the nanotubes. This property of CNFETs makes them very suitable for the multiple- V t design method. The proposed circuits are simulated exhaustively, using Synopsys HSPICE with 32 nm-CNFET technology in various test situations and different supply voltages. Simulation results demonstrate great improvements in terms of speed, power consumption and insusceptibility to process variations with respect to other conventional and state-of-the-art 32 nm complementary metal-oxide semiconductor and CNFET-based ternary circuits. For instance at 0.9 V, the proposed ternary logic and arithmetic circuits consume on average 53 and 40 less energy, respectively, compared to the CNFET-based ternary logic and arithmetic circuits, recently proposed in the literature.

Field programmable analogue array implementation of fractional step filters

Abstract: In this study, the authors propose the use of field programmable analogue array hardware to implement an approximated fractional step transfer function of order (n+α) where n is an integer and 0 < α < 1. The authors show how these filters can be designed using an integer order transfer function approximation of the fractional order Laplacian operator sα. First and fourth-order low- and high-pass filters with fractional steps from 0.1 to 0.9, that is of order 1.1–1.9 and 4.1–4.9, respectively, are given as examples. MATLAB simulations and experimental results of the filters verify the implementation and operation of the fractional step filters.

SiC and GaN devices – wide bandgap is not all the same

Abstract: Silicon carbide (SiC)-diodes have been commercially available since 2001 and various SiC-switches have been launched recently. Parallelly, gallium nitride (GaN) is moving into power electronics and the first low-voltage devices are already on the market. Currently, it seems that GaN-transistors are ideal for high frequency ICs up to 1kV (maybe 2kV) and maximum a few 10A. SiC transistors are better suited for discrete devices or modules blocking 1kV and above and virtually no limit in the current but in that range they will face strong competition from the silicon insulated gate bipolar transistors (IGBTs). SiC and GaN Schottky-diodes would offer a similar performance, hence here it becomes apparent that material cost and quality will finally decide the commercial success of wide bandgap devices. Bulk GaN is still prohibitively expensive, whereas GaN on silicon would offer an unrivalled cost advantage. Devices made from the latter could be even cheaper than silicon devices. However, packaging is already a limiting factor for silicon devices even more so in exploiting the advantage of wide bandgap materials with respect to switching speed and high temperature operation. After all, reliability is a must for any device no matter which material it is made of.

Wide band-gap power semiconductor devices

Abstract: The recent progress in the development of high-voltage SiC, GaN and diamond power devices is reviewed. Topics covered include the performance of various rectifiers and switches, material and process technologies of these wide band-gap semiconductor devices and future trends in device development and industrialisation.