Fast and wire multiplexing circuits

Abstract

An apparatus for a multiplexor circuit includes a passgate circuit coupled to receive input signals and corresponding select signals comprising a subset of the input signals and select signals received by the multiplexor. The apparatus also includes a default circuit coupled to receive the select signals and coupled to an output node of the passgate circuit. If none of the select signals is asserted, the default circuit supplies a default voltage on the output node. Other passgate circuits and default circuits may be included coupled to other subsets of the input signals and select signals, and an output circuit may be included with inputs coupled to the output nodes of the passgate circuits. The default voltage may represent a logical value which allows the value from another passgate circuit to control the output of the output circuit.