Power saving static-based comparator circuits and methods and content-addressable memory (cam) circuits employing same

Abstract

Static-based comparators and methods for comparing data are disclosed. The static-based comparator is configured to selectively switch at least one comparator output in response to a comparison of corresponding data with compare data, and a validity indicator for the data. If the validity indicator indicates valid data, the static-based comparator switches to drive the comparator output indicating either a match or mismatch between corresponding compared data. If the validity indicator indicates invalid data, the static-based comparator provides a mismatch on the comparator output without switching the static-based comparator regardless of whether or not the data matches the compare data. In this manner, the static-based comparator does not dissipate power switching the comparator output for data marked invalid. The static-based comparator can be employed in content addressable memories (CAMs) for comparing one or more bits of tag data to corresponding bit(s) of compare data.