Combinational Building Blocks

Multiplexer

Logic Using Multiplexer

We can use multiplexer to implement a look up table (LUT). For example, below is a 3-bit input LUT (3-LUT) implemented using a multiplexer.

3-LUT can implement any 3-bit input function!

Maybe a better way to visualize this is to think about the the SoP, the function we want to implement using gates is just a sum of products. But, by using a multiplexer, we can actually integrate each minterm in a multiplexer and then use the number of variable bits as select bits.