J.L. Visschers

Pulse-width modulation pre-emphasis applied in a wireline transmitter, achieving 33 dB loss compensation at 5-Gb/s in 0.13-/spl mu/m CMOS

A transmitter pre-emphasis technique for copper cable equalization is presented that is based on pulse-width modulation (PWM). This technique is an alternative to the usual 2-tap symbol-spaced FIR (SSF) pre-emphasis. The technique uses timing resolution instead of amplitude resolution to adjust the filter transfer function, and therefore fits well with future high-speed low-voltage CMOS processes. Spectral analysis and time domain simulations illustrate that PWM pre-emphasis offers more relative high frequency boost than 2-tap SSF. Only one coefficient needs to be set to fit the equalizer transfer function to the channel, which makes convergence of an algorithm for automatic adaptation straightforward. A proof-of-concept 0.13-/spl mu/m CMOS transmitter achieves in excess of 5 Gb/s (2-PAM) over 25 m of standard RG-58U low-end coaxial copper cable with 33 dB of channel loss at the Nyquist frequency (2.5 GHz). Measured BER at this speed and channel loss is <10/sup -12/.

A Radiation Hard Bandgap Reference Circuit in a Standard 0.13

With ongoing CMOS evolution, the gate-oxide thickness steadily decreases, resulting in an increased radiation tolerance of MOS transistors. Combined with special layout techniques, this yields circuits with a high inherent robustness against X-rays and other ionizing radiation. In bandgap voltage references, the dominant radiation-susceptibility is then no longer associated with the MOS transistors, but is dominated by the diodes. This paper gives an analysis of radiation effects in both MOS devices and diodes and presents a solution to realize a radiation-hard voltage reference circuit in a standard CMOS technology. A demonstrator circuit was implemented in a standard 0.13 mum CMOS technology. Measurements show correct operation with supply voltages in the range from 1.4 V down to 0.85 V, a reference voltage of 405 mV plusmn 7.5 mV ( sigma = 6 mV chip-to-chip statistical spread), and a reference voltage shift of only plusmn1.5 mV (around 0.8%) under irradiation up to 44 Mrad (Si).

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This paper presents a study on the dielectric behavior of SU-8 photoresist. We present measurements on the leakage current levels through SU-8 layers of varying thickness. The leakage current is dominated by thermionic emission. We have further determined the dielectric strength of SU-8 to be 4.4 MV cm−1. The remarkably high dielectric strength allows the material to be used for high-voltage applications.

m CMOS Technology

A digital transmitter pre-emphasis technique is presented that is based on pulse-width modulation, instead of finite impulse response (FIR) filtering. The technique fits well to future high-speed low-voltage CMOS processes. A 0.13 /spl mu/m CMOS transmitter achieves more than 5 Gb/s (2-PAM) over 25 m of standard RG-58U low-end coaxial copper cable. The test chip compensates for up to 33 dB of channel loss at the fundamental signaling frequency (2.5 GHz), which is the highest figure compared to literature.

The electrical conduction and dielectric strength of SU-8

Abstract Recent theoretical damage material models describe the dynamic development of voids and microcracks in materials under plastic deformation. For these models, experimental verification is needed. We propose direct and non-destructive observation of the propagation of material damage by measuring changes in transmission of X-rays penetrating a stressed material, using a photon-counting X-ray imager. The present contribution aims to demonstrate the applicability of silicon and gallium-arsenide devices for X-ray transmission measurements with a specimen of high-ductile aluminium alloy under study. The first experiments to determine the resolution and the sensitivity of the proposed method with the Medipix-1 pixel detector are presented.

CMOS transmitter using pulse-width modulation pre-emphasis achieving 33 dB loss compensation at 5-Gb/s

A new apparatus for detection of νμ → ντ oscillation has been successfully constructed and operated by the CHORUS Collaboration for the CERN-WA95 experiment. The design, implementation and performance of the electronic trigger system is described. A trigger efficiency of 99% was measured for νμ charged-current events and 90% for neutral-current events.

First tests of a Medipix-1 pixel detector for X-ray dynamic defectoscopy

Abstract The 12C(e, e′p) reaction has been studied in the dip region, at an energy transfer ω = 212 MeV and a three-momentum transfer |q| = 270 MeV/c. The data cover a missing energy range 0–180 MeV and include missing momenta up to 750 MeV/c. The cross sections, measured at various angles between the detected proton and q, show a clear signature for two-nucleon knock-out. At large angles, the measured strength can mainly be attributed to the coupling of the virtual photon to pion exchange currents and intermediate Δ-excitation. The data at small angles cannot be explained by these mechanisms alone. It is suggested that additional strength originates from the emission of a correlated nucleon pair.

The trigger system of the CHORUS experiment

This article presents a detector system consisting of three components, a CMOS imaging array, a gaseous-detector structure with a Micromegas layout, and a UV-photon sensitive CsI reflective photocathode. All three elements have been monolithically integrated using simple post-processing steps. The Micromegas structure and the CMOS imaging chip are not impacted by the CsI deposition. The detector operated reliably in He/isobutene mixtures and attained charge gains with single photons up to a level of 6x104. The Timepix CMOS array permitted high resolution imaging of single UV-photons. The system has an MTF50 of 0.4lp/pixel which corresponds to approximately 7lp/mm.

Two-nucleon knock-out investigated with the semi-exclusive 12C(e, e′p) reaction

An important feature of hybrid semiconductor pixel detectors is the fact that detector and readout electronics are manufactured separately, allowing the use of industrial state-of-the-art CMOS processes to manufacture the readout electronics. As the feature size of these processes decreases, faster and more complex electronics can be designed and manufactured. Furthermore, most new CMOS processes are optimised for use with digital circuits, making the design of precise analog electronics a difficult task. Hence, the sooner the data is converted to the digital domain, the better the technology can be used. We have studied the possibility of adding energy sensitivity to the single photon counting capability of pixel detectors. To know not only the number of X-ray photons but also their energies (or wavelenghts), will increase the information content of the resulting image, given the same X-ray dose. In order to do this, a small and low power ADC is added to each pixel. We have studied different types of analog-to-digital converters that can be implemented inside the pixel electronics of a pixel detector.

A UV sensitive integrated micromegas with timepix readout

GridPix detector prototypes have been made using a TimePix pixel chip and a PSI 46 pixel chip. A system of discharge protection has been successfully tested. GridPix detectors have been tested using cosmic rays, a 90Sr source and the T9 test beam facility at CERN. GridPix detectors perform well for 3D track reconstruction, dE/dx measurements and transition radiation detection.