Groundbounce in ASIC´s: model and test results

Groundbounce is the noise produced by simultaneous switching of drivers in an ASIC, due to excessive current drawn from the power supply at the time of switching. This noise may cause delay and false triggering problems at the functional level, as well as emissions problems due to the fast rise time and amplitude of current spikes induced. Test results which attest to the seriousness of the groundbounce problem in large ASICs are presented. The importance of the positioning of switching drivers as a factor in reducing groundbounce is discussed. The model of groundbounce is detailed to include layout and package parameters, in order to more accurately calculate the effective inductance value to be used for predictions. The results presented correspond to groundbounce voltages measured in one test chip mounted on a PGA package