A Reduced Output Ringing CMOS Buffer

In a multichip module, the parasitic elements of the interconnections influence the performance of the devices enclosed in the package. Phenomena such as ground bounce, cross-talk, propagation delay, and over/undershoot will degrade the data signal integrity. This brief describes an output buffer structure, consisting of a double feedback loop. It reduces the oscillating behavior caused by parasitic elements in the data lines during the final phase of an output transition. The proposed structure employs simultaneous monitoring of the pad voltage and of the supplied current. Precise control of these parameters will reduce the sensitivity to reflection effects and inductive parameters of the package and printed circuit board tracks.