Evaluating USB 2.0 Signal Integrity over Non-USB-Optimized Connectors

Sammanfattning

This thesis was performed for the company Actia Nordic AB and researches the viability of transmitting USB data using a 16-pin Molex Mini50 connector that is not made for that purpose. The intent is to improve product compactness by consolidating multiple data connections into a single unified connector, with enough pins to accommodate these, instead of utilizing multiple separate connectors. To evaluate the connector, a 3D simulation using a model of the connector pins is first performed to analyze three distinct implementation candidates. Based on the simulation results, a circuit board is then produced and used to make measurements to evaluate and analyze electromagnetic compatibility (EMC), with a focus on conducted and radiated emissions, and to compare the signal integrity of the implementation candidates. The results suggest that implementing USB with this connector is indeed viable, and that the best configuration may be achieved when using the edge pins on either side of the connector. The wire pairs should use adjacent pins that are as close together as possible, with a minimal gap between the differential signal pins, to minimize the electric field created. The measured data is, however, not sufficient to adequately conclude whether this is the most optimal implementation, particularly regarding emissions. Deeper analyses would be needed to validate the EMC performance and how it may be affected in the wider scope of incorporating additional parallel data connections.