Cody Dowling, | System Engineer, Problem Solver, Consultant, Dallas, TX, USA – January 29, 2018

Cody Dowling used the EMxpert for R&D and design

I used the EMxpert system during the time I worked for two different semiconductor companies as a Systems and Applications engineer. In my opinion, it is an incredible time saver and should be as much a part of the EMC engineer’s toolbox as is a sniffer probe or a spectrum analyzer. As a consultant now, I explain the unit in my training sessions as being similar to “… an array of sniffer probes that allows you to see EMI.”

My first experience with EMxpert was while designing evaluation boards for Class D amplifier integrated circuits (ICs). I had been spending tons of time (and money!) in the EMI chamber at our local testing facility trying to get the evaluation boards (EVB) to pass FCC testing. A passing EVB would assure our customers that our parts could be made to pass and that we knew how to help them get their board to pass if they used our IC. Of course, switching amplifiers like these can cause significant emissions problems, which usually present as common-mode noise on the PCB and power/speaker cables. The problems are abated by proper board stack up, trace routing, and component placement, but there are cost trade-offs with multi-layer boards and passive components. Since we had to make several trade-offs related to the PCB configuration, we needed to quickly understand which layout we should recommend from an emissions perspective, while keeping external components and board costs to a minimum.

Similar to how a thermal image gives a visual representation of heat, the EMxpert offered the unique ability to see the relative emissions levels present in our EVBs. The grid pattern on the EMxpert antenna pad, and the ability to import and overlay PCB Gerber files were invaluable, because I could correlate both the amplitude and frequency of emissions with physical structures in the system being tested.  I could then perform iterative modifications (i.e. tuning LC resonances, modifying snubbers, or adding common-mode chokes and other passives) and quickly see how much those modifications improved or exacerbated a given problem. I also used the EMxpert unit to evaluate different operational modes (i.e. spread spectrum, slew-rate controlled, etc.) and could immediately measure how much of a difference these modes made in the emissions.

After a time of using it, we began to get a sense for how much certain levels on the EMxpert in our lab would affect us in the chamber during compliance testing. All of this saved time and money because I could go to the chamber with a nearly optimal solution and just do final tweaking as needed. That is much more powerful than just passing a sniffer probe over a piece of equipment manually. After becoming confident in the EMxpert unit, we began to use the unit on both our designs and those of our customers, with great success.

As a Systems Engineer and product definer, I also used the EMxpert unit to measure relative emissions from various IC packages, bond wire configurations, PCB traces, cables, connectors, and passive component body-sizes. This allowed us to quickly compare various design options and configurations- either within our own device or against a competitor device. This data was then used to inform the chip designers about different design trade-offs as they related to EMI, through the product definition document. I could also use this information to give suggestions to the application engineer regarding proper component selection and layout recommendations.

I highly recommend EMxpert unit to gain insights into difficult EMI challenges. Once familiar with its operation, I believe that you’ll likely find it very useful.



About EMSCAN
EMSCAN is the world leading developer of FAST magnetic very-near-field measurement technologies and applications since 1989, providing real-time test solutions to antenna and PCB designers and verification engineers, without the need for a chamber.

The EMxpert, a family of compact EMC and EMI diagnostic tools, and the RFxpert, a family of antenna measurement tools, enable engineers to quickly optimize their designs. EMSCAN solutions dramatically increase designer productivity and substantially reduce time-to-market and project development costs. www.emscan.com