Hjalmar Hesselbom

Techniques for reducing switching noise in high speed digital systems

Simultaneous switching noise (SSN) caused by parasitic inductance in the power supply distribution network is a severe problem in high speed digital circuits and systems. The influence of SSN, negligible when rise/fall time is long (>5 ns), becomes an important factor, limiting circuit performance in the sub-nanosecond rise time region. This paper presents simulation results of SSN in high speed digital systems. Technical solutions for reducing SSN in the light of current developments of advanced packaging and assembly technologies are discussed. A quantitative comparison of SSN in digital systems implemented with conventional as well as advanced assembly techniques is given.

All-printed diode operating at 1.6 GHz.

Significance Printed electronic labels and stickers are expected to define future outposts of the communication web, as remote sensors, detectors, and as surveillance technology, within the Internet-of-things concept. It is crucial to couple such technology with standard communication systems that commonly operate at gigahertz frequencies. To accomplish this, ultra–high-frequency rectification components manufactured in a low-temperature printing process are necessary. Here, we report an all-printed diode operating above 1 GHz, achieved using a combination of Si and NbSi2 microparticles. The diode was integrated with a flexible antenna and a printed electrochromic display indicator to successfully demonstrate remote transfer of signal and power from a standard Global System for Mobile Communications phone to the resulting e-label. Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications.

Investigation of high-speed pulse transmission in MCM-D

Experimental investigation of high-speed pulse transmission in an MCM-D modules has been carried out. By using advanced CMOS dice (74AC240) and a fast comparator (SP93 808), and high frequency MCM-D technology, it is demonstrated that a long aluminum lossy line (8.0 cm) can limit the maximum frequency of an MCM-D module. On the other hand, the maximum frequency is limited by the CMOS circuits when the line length is equal or shorter than 6.0 cm. For a 5.0-cm line, best pulse integrity is obtained when a 40- Omega series resistor termination is utilized. From the half fall time measured with the comparator, the estimated maximum clock frequency in the module is about 1 GHz for a 5.0-cm stripline with impedance matched termination. Crosstalk is negligible between parallel striplines with a 75- mu m pitch in the module. On the other hand, crosstalk in the module package is observed. >