AC Termination For Signal Busses
Written By: Ben Smith
Abstract: DOWNLOAD TECHNICAL PAPER
The predominant direction of modern electronic system design is towards higher speed and efficiency. This is not to say that efficiency was not an issue in previous designs, but as clock speeds increase, many elements that once were treated as ideal cannot be treated in this manner any longer. Digital system designers are faced with critical issues dealing with maintaining signal integrity while balancing numerous other inhibiting factors. Perhaps one of the more menacing non-ideal effects can be seen in signal transmission through bus lines. Gone are the days when a trace of metal could be treated as a loss less element. Today’s high speed busses require a thorough evaluation using transmission line techniques. Factors such as propagation delays, signal reflections, and power consumption must be taken into account when designing high speed digital systems. Effective signal line termination maximizes the performance of the whole system by improving signal integrity while abiding by all other constraints. The termination technique dealt with in this paper is AC termination which is simply the connection of a resistor in series with a capacitor to ground.