POWER SAVING STATIC-BASED COMPARATOR CIRCUITS AND METHODS AND CONTENT-ADDRESSABLE MEMORY (CAM) CIRCUITS EMPLOYING SAME

摘要

Static-based comparators (78) and methods for comparing data are disclosed. The static-based comparator (114) is configured to selectively switch at least one comparator output (110) in response to a comparison of corresponding data (96) with compare data (98), and a validity indicator (120) 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.