MultiplexerDemultiplexer

MultiplexerDemultiplexer: In electronics, a multiplexer (MUX) is a digital switch that selects one of several input signals and forwards it to a single output. A demultiplexer (DEMUX) performs the inverse operation, taking a single input and routing it to one of several outputs. In many designs, a single integrated circuit can be configured to act as either a MUX or a DEMUX depending on the select signals and wiring; such devices are sometimes described as multiplexer/demultiplexers.

Both types rely on control inputs called select lines to determine routing. A MUX uses select lines to connect exactly one of its inputs to the output, while a DEMUX uses a data input along with select lines to determine which output receives the data. Enable or strobe inputs can disable the device to prevent contention or to isolate the channel.

Common implementations include digital multiplexers and demultiplexers in the 74xx and 74HC families, as well as analog versions such as the 4051/4052/4053 and related devices. Example configurations include 2-to-1, 4-to-1, or 8-to-1 multiplexers, and corresponding demultiplexers of the same channel counts. Larger systems often use MUX/DEMUX networks to share a single data line among many sources or destinations, or to route signals as part of time-division multiplexing and bus architectures.

Key considerations when selecting a MUX/DEMUX include channel count, propagation delay, input/output impedance, voltage levels, enable behavior, and fan-out. Proper design avoids glitches during select transitions and ensures clean signal timing in synchronous circuits.