Civil Engineering Reference
In-Depth Information
making use of application-specific boundaries, any decision on the applicability of
the transceiver can be taken. In 2008, for the first time German car manufacturers
jointly had published such a specification of requirements, which, from that point
of time on, represents the basis for EMC release.
Measurement of Emissions in the Frequency Domain—1 Ω/150 Ω Method
The measurement process of the emission spectrum (electromagnetic emission
(EME) test) of semiconductor devices is described in the standard IEC 61967: “In-
tegrated circuits—Measurement of electromagnetic emissions”. This standard is
subdivided into a general part I, which contains general definitions for all measure-
ment methods, as well as into five further parts for each of the individual measure-
ment methods, respectively. The 1 Ω/150 Ω method (IEC 61967, Part 4) is based on
the direct measurement of lines-based noise of semiconductor devices. This method
assumes that any internal noise, which is generated by high-speed current or voltage
swings, will proceed over the pins to the electronic circuit board or to the wiring
harness, from where the noise is radiated over cable loops or any other antenna-like
structure. For the most commonly used body shapes of ICs (with the exception of
large microprocessors), the internal parasitic antenna structures, which are able to
radiate as a function of frequency, are significantly smaller than those of PCBs. As
such, the external radiation is predominant in the application. In this case, the mea-
surement method is applicable for the comprehensive characterization of the noise
emission of the semiconductor device. For the analysis of noise emission of the
global pins of CAN transceivers, the HF measurement technique of noise voltage is
applied, using a voltage probe of 150 Ω. This technique represents one of the two
potential measurement methods of the standard.
Measurement of Noise Immunity in the Frequency Domain—Direct Power Injection
The measurement of noise immunity of semiconductor devices against narrowband
radiated noise is performed analogously to noise emission described in the standard.
IEC 62132 “Integrated circuits—Measurement of Electromagnetic Immunity” is
divided into a general part I and four further parts describing the individual mea-
surement methods. In this standard, the test methods also are subdivided into those
ones for direct field immission into the IC body and those ones for methods of
noise injection over the pins. In the frequency range below f = 1 GHz, the direct
immission can be neglected for a multitude of semiconductor devices. Applied to
CAN transceivers, the direct power injection (DPI) method (IEC 62132-4) emulates
those parts of noise, which are generated by field immission into the wiring harness
or into antenna-like structures of the PCB of a component, from where the noise
is line-borne fed into the semiconductor device. For this purpose, a noise power
corresponding to this field immission is directly injected into the global pins of the
CAN transceiver.
