Pasquale Tommasino

A high speed truly IC random number source for smart card microcontrollers

The design of a high speed IC random number source macro-cell, suitable to be integrated in a Smart Card microcontroller, is presented. The direct amplification of thermal noise is exploited and an accurate and low area demanding offset zeroing system has been developed in order to increase the statistical quality of the generated bit sequences. Using a 0.18 /spl mu/m n-well CMOS process, a prototype has been fabricated and measured, obtaining a random behavior for an output data rate up to 40 Mb/s.

A Novel Wake-Up Receiver with Addressing Capability for Wireless Sensor Nodes

Emerging low-power radio triggering techniques for wireless motes are a promising approach to prolong the lifetime of Wireless Sensor Networks (WSNs). By allowing nodes to activate their main transceiver only when data need to be transmitted or received, wake-up-enabled solutions virtually eliminate the need for idle listening, thus drastically reducing the energy toll of communication. In this paper we describe the design of a novel wake-up receiver architecture based on an innovative pass-band filter bank with high selectivity capability. The proposed concept, demonstrated by a prototype implementation, combines both frequency-domain and time-domain addressing space to allow selective addressing of nodes. To take advantage of the functionalities of the proposed receiver, as well as of energy-harvesting capabilities modern sensor nodes are equipped with, we present a novel wake-up-enabled harvesting-aware communication stack that supports both interest dissemination and converge casting primitives. This stack builds on the ability of the proposed WuR to support dynamic address assignment, which is exploited to optimize system performance. Comparison against traditional WSN protocols shows that the proposed concept allows to optimize performance tradeoffs with respect to existing low-power communication stacks.

A synthesis-oriented approach to design microwave multidevice amplifiers with a prefixed stability margin

A design methodology that allows forcing a prefixed stability margin on microwave and millimeter-wave multidevice amplifiers during the synthesis procedure performed by CAD tools is proposed. To the best of our knowledge, for the first time expressions equivalent to stability margins have been determined to guide CAD optimizers to design circuits stable under parameter variations. Stability margins discussed in this paper allow inclusion of stability requirements among yield specifications in a rigorous way. A case study of a 4-FET distributed amplifier design is presented where stability under parameter variations has been achieved by using the proposed methodology.

A method for microwave characterization of LiNbO 3 modulators

A procedure to extract the S-parameters of both the active section and the input and output coplanar tapers of Mach-Zehnder modulators is proposed. The S-parameters of the three sections of the modulator have been successfully extracted up to 30 GHz from measurements and EM simulations performed on proper test structures.

Necessary and sufficient conditions for the stability of microwave amplifiers with variable termination impedances

New criteria to check conditional stability of microwave amplifiers with input and output terminations varying in pre-specified circular regions surrounding complex nominal values are proposed. Necessary and sufficient conditions are provided both in terms of the immittance parameters /spl lambda//sub ij/ (i.e., z/sub ij/,y/sub ij/,g/sub ij/, or h/sub ij/) and in terms of the scattering parameters s/sub ij/. Proposed conditions can be easily implemented in any commercial computer-aided design tool and are suitable to be used as design goals within an optimization routine: this allows to optimize the tradeoff between stability constraints under termination variations and performance in a yield-oriented design flow. A case study, in which a distributed amplifier has been designed, shows the advantages of the proposed approach.

An active balun for high-CMRR IC design

A circuit topology that provides large bandwidth single-ended to differential conversion is presented. The proposed cell is based on a differential pair where feedback on common mode signal provides about 6 dB conversion gain increase, together with attenuation of common mode signal. Small-signal characterisation is presented, based on a block decomposition of the cell. Measurements on a SiGe test IC show more than 5 dB of gain improvement with respect to a simple differential pair.

A new topology for a transimpedance amplifier with postfabrication bandwidth adjustment

4. CONCLUSION wx The reflectivity properties of a simulated simpler LTBC 8, 9 wx and NTBC 5 were studied for a typical ground-based TDP problem. For a fixed propagation step size, the LTBC demon- strated a minimum of reflectivity with respect to the trans- verse step size. This property allows a larger transverse step size when the LTBC is used in comparison with the NTBC and, combined with the simplicity of the LTBC, ensures rapid and adequate calculations. According to the results, for the above-described TDP problem, it can be recommended to start the calculations with a moderate propagation step size D x and a transverse step D z in the range 0.4)0.7 m. With proper choice of the discretization step sizes, the LTBC may be useful in practical applications requiring real-time execu- tion and small computational resources. ABSTRACT: In this paper, we present a new topology for a tran- simpedance amplifier that allows postfabrication bandwidth adjustment by using a controloltage between the ground and the supply leel. Simulated results using HEMT and HBT technologies show a significant () bandwidth enhancement 25)45% with a negligible noise penalty. Q 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 47)51, 2000.

Integrated Design Tool for fiber-optic analog links

An integrated tool for the analysis and design of optical analog links is proposed, in order to permit optimization of joint performance of the modulator and of its electrical driver within a microwave circuital CAD. The tool comprises a circuital model of the Mach-Zehnder modulator, and a FEM simulator for modulator design from a given physical and geometrical structure. A case study of design and analysis of a broadband link operating at frequencies as high as 35 GHz is presented, to illustrate advantages of the proposed tool.

A synthesis-oriented conditional stability criterion for microwave multidevice circuits with complex termination impedances

In this work, a new conditional stability criterion for multidevice circuits is proposed, in order to guarantee stability in spite of input and output termination variations in regions surrounding complex nominal values. A check of this criterion can be implemented in a commercial CAD environment, and this allows imposing stability from within an optimization routine. A design methodology to synthesize multidevice circuits with complex termination impedances, which are stable under both process parameters and terminations variations, is proposed.

Fully Differential Class-AB OTA with Improved CMRR

This paper presents a fully differential class-AB current mirror OTA that improves the common-mode behavior of a topology that presents very good differential-mode performance but poor common-mode rejection ratio (CMRR). The proposed solution requires a low-current auxiliary circuit driven by the input signal, to compensate the effect of the common-mode input component. Simulations in 40-nm CMOS technology show a net reduction of common-mode gain of more than 90dB without affecting the differential-mode behavior; a sample-and-hold amplifier exploiting the proposed amplifier has also been simulated.