S. Di Pascoli

Single chip 1.8 GHz band pass LNA with temperature self-compensation

This paper presents the design and post-layout simulation results for a single chip 1.8 GHz band-pass LNA using the boot-strapped inductor approach. It is characterized by a bandwidth of 54 MHz, a minimum noise figure of 1.8 dB, a transducer power gain of 27.5 dB, an input linearity range up to -20 dBm and a power consumption of 20.7 mW. The circuit features a proper self-adaptive compensation to achieve robustness against temperature variations.

Base coupled differential amplifier: a new topology for RF integrated LNA

A new topology of bipolar low noise amplifier (LNA) for RF applications, named base coupled differential (BCD), is presented. The proposed approach is compared by simulation against most classical topologies. The BCD configuration has the key advantage to join an integrated matching on a single-ended input with a differential output. This is done by using down-bond wiring, so that no integrated inductors are needed. The main advantages of this new topology are a drastic area reduction and an increased linearity range (or a reduced biasing current with the same linearity) together with a noise figure (NF) and voltage supply reduction. Particularly, the BCD LNA presented in this paper has been designed for 2.44GHz frequency operation. It is characterized by a NF of 1.93dB, a voltage gain (Av) of 19.5dB, an input impedance of 50Ωa third Input-referred Intercept Point (IIP3) of -7.25dBm and a dissipated power (PD) equal to 19mW. Copyright

Temperature controlled oven for low noise measurement systems

Low frequency noise measurements are often applied to the characterization of electron devices. When such measurements have to be performed on electronic components maintained at a given temperature, the thermal stability of the oven used to this purpose becomes a major concern. In this paper we present the realization of a high thermal stability oven, purposely designed for low frequency noise measurement devoted to the characterization of electromigration in metal interconnections of integrated circuits. The prototype demonstrates that the contribution of the thermal fluctuations of the oven to the background noise of the measurement system is negligible down to frequencies as low as 10 mHz in the temperature range 25-150/spl deg/C.

Temperature coefficient of resistance fluctuations during electromigration in Al lines

A simplified model is presented for the degradation of the conducting properties of Al stripes subjected to electromigration. Such a model has been used in order to investigate the role of grain boundaries in the behavior of the temperature coefficient of resistance (TCR). The results obtained by means of two dimensional simulations allow us to give a simple interpretation of the experimentally observed fluctuations of the TCR during electromigration.

A single-chip 1.8 GHz image reject RF receiver front-end with boot-strapped inductors

A fully integrated RF front-end for 1.8 GHz wireless receiver is presented. The circuit is based on a single-conversion heterodyne architecture with a band-pass low noise amplifier and an image-reject mixer. Bootstrapped inductors are used to realize the high quality factor inductors of the tunable LC active filters in the variable gain low noise amplifier. The front-end, which has been designed for a 50 GHz bipolar process, presents an overall image-rejection greater than 62 dB at 100 MHz of intermediate frequency. The main characteristics of this design are a gain of 17.3 dB, a bandwidth of 45 MHz, a linearity range up to -20 dBm, a power consumption of 120 mW, a low area on die and a low cost, since no external components in the RF and IF signal paths are needed.

Study of Hot-spot Phenomena in Cellular Power Transistors by Analytical Electro-Thermal Simulation

The cellular power transistors are affected by the socalled hot spot phenomenon, a current crowding within few cells occurring for high power conditions, which decreases the device operating range. The onset of this phenomenon was studied under a wide range of electrical and thermal boundary conditions by means of a fast electro-thermal simulation procedure operating in the steady-state regime and using explicit analytical relationships for the temperature mapping. Furthermore, the results of experimental electrical characterizations performed on some samples were in agreement with the foreseen data.

Wireless sensor network for derailment detection in freight trains powered from vibrations

We present a network of wireless ultra-low-power sensors with the main purpose of detecting the derailment of a freight car and alerting the engineer in the cab of the leading locomotive. Due to the lack of a power supply in freight cars, we plan to rely on energy scavenging from vibrations. This implies that the energy requirements of the system must be minimized, choosing ultra-low-power hardware and operating it in active mode only for a small fraction of the time. We discuss the approach that we are currently pursuing, focusing, in particular, on the choice of hardware and the communication protocol.

A new differential LNA topology for wireless applications

In this paper a new topology of differential low noise amplifier for wireless applications is presented. This solution allows a drastic area reduction, with respect to traditional emitter coupled topology, since it makes it possible to achieve integrated matching at the input by using only down-bond wiring. In this way no integrated inductors are needed. As shown by simulations, an increased linearity range can also be obtained, without impairing the noise figure. As an example of this new solution, a LNA has been designed for 2.44 GHz frequency operation. The main characteristics of this amplifier are: a noise figure of 1.56 dB, a voltage gain of 19.5 dB, an input impedance of 50 /spl Omega/, an input-referred 3/sup rd/ intercept point of -7.25 dBm and a dissipated power equal to 19 mW.

Fully integrated heterodyne RF receiver for ISM band applications

A fully integrated RF single-conversion heterodyne receiver front-end for ISM band (2.44 GHz) wireless applications is presented. The circuit realizes a high image rejection by exploiting a band pass low noise amplifier and an image-reject mixer according to the Hartley architecture. The front-end has been designed on a 50 GHz cut-off frequency bipolar process. The main characteristics of this design are an overall image-rejection greater than 57 dB at 110 MHz of intermediate frequency, a transducer power gain of 32 dB, a bandwidth of 80 MHz, an input linearity range up to -20 dBm, a power consumption of 96 mW, and finally, it does not require external components.

Simulation of electromigration noise in polycrystalline metal stripes

Abstract We have performed the Monte Carlo simulation of electromigration noise in polycrystalline metal stripes, based on a two-dimensional model which takes into account both the role of grain boundaries and the effect of current density redistribution in the stripe. The noise spectrum has the characteristic 1/fγ (γ≈2) behavior, and the total noise power strongly increases with increasing damage of the stripe. The results of the simulation exhibit a substantial qualitative agreement with experiments, giving confidence in the capability of our model of including the relevant physics involved in the failure process.