Application of chip-level EMC in automotive product design

Abstract

Integrated circuits (ICs) are often the source of the high-frequency noise that drives electromagnetic emissions from electronic products. A case study is presented where emissions from a printed circuit board containing an automotive microcontroller are reduced significantly through analysis of the coupling mechanisms from the chip to the board and attached cables. Noise generated by the IC is explored through measurements in a semi-anechoic chamber and TEM cell, through near-field scans, and through modifications to the printed circuit board. Noise is driven by the IC through both power and I/O connections. Results show that a ferrite in series with I/O power in this application reduced emissions by 10 dB or more at critical frequencies. Possible causes for emissions from the IC and modifications that might reduce these emissions are discussed.

Far-end crosstalk reduction in adjacent PCB traces employing High/Low-Z configurations

“…Normally, the first line of defence is to mitigate the radiation source by reducing the current strength, slewing the rise/fall time of the digital signal (e.g. by adding series resistors or ferrites [1]) or shortening/straightening the high-frequency trace. Though such countermeasures may provide a limited improvement, they may not even be an option for a given design (e.g.…”

Far-end crosstalk reduction in PCB interconnects using stepped impedance elements and open-circuited stubs

“…Normally, the first line of defence is to mitigate the radiation source by reducing the current strength, slewing the rise/fall time of the digital signal (e.g., by adding series resistors or ferrites [1]) or shortening/straightening the high‐frequency trace. Though such countermeasures may provide a limited improvement, they may not even be an option for a given design (e.g., for signal integrity constraints).…”