Models: what for?

Equipment designers want to predict the parasitic emission of their equipment, such as the automotive engine control system shown here, by courtesy of Siemens Automotive SA. The short distance scan of the equipment shows specific areas with strong emission (In red), and other areas with low emission (in blue). Most of the time, the emission measurement is performed once the equipment is fabricated, and software tools do not predict accurately the measured emission.

Offering an EMC model to customers is a commercial argument. Equipment designers will prefer to buy an IC for which measurements are available (Such as TEM cell measurements or conducted measurements). But they would prefer an IC supplier also offering the model that permits a prediction of the conducted or radiated energy at printed circuit board level.

Supplier 1	Supplier 2	Supplier 3

EMC handled at end of design cycle

Usually, the EMC compliance is tested at the end the design cycle, once the IC is placed on the equipment or in a specific EMC test board. An emission level higher than the specification lead to a redesign, which usually consists in adding on-chip decoupling, adding more supply pins, or changing the floorplanning of the chip. Theses costly redesigns also include months of delay. EMC is the second cause of redesigns in the automotive industry, which is very much concerned by electromagnetic compatibility compliance.

Target methodology

The target methodology consists in adding specific tools, design guidelines and appropriate training in order to iterate in the design phases and to ensure the EMC compliance prior to fabrication. If the simulation flow is validated the IC once fabricated will comply to electromagnetic compatibility regulations. This flow should soon become reality as major IC manufacturer conduct research and development in this area, and start getting good results. However, tools are not mature, the design guidelines are somehow an expert-level knowledge, and the training is hard to setup due to the very wide aspects treated by EMC for ICs.