Techniques to minimise cross-talk and ringing in printed circuit boards

The problems associated with design of printed circuit board (PCB) are many fold, if one has to ensure designed performance and compliance to relevant electromagnetic compatibility standards. The signal integrity within the PCB needs to be analysed before finalisation of PCB routing and needless to say that simulation is must. Present day simulation tools will highlight the signal integrity problems better than the conventional methods. But, the solutions to the problems needs to be obtained by the PCB designer and that requires good understanding of transmission line theory and input-output buffer information specifications (IBIS) of integrated circuits used. The major sources of signal integrity problems are the crosstalk and ringing in the PCB tracks (otherwise transmission lines). The technical paper proposes different techniques to minimise these effects in a PCB. A novel technique of equalising filter design for cross-talk minimisation is presented. Also highlighted are the analysing capabilities and limitations of different software packages available in the market.