The HGSEMI 74HC138N is an 8-to-3 line decoder/demultiplexer with signal switches. It is a 16-pin dual in-line package RoHS compliant device, ideal for applications such as address decoding and data routing. The signal switch is used to enable and disable output signals. The switch can be used to selectively enable or disable individual output lines, allowing for an easy implementation of common-bus systems. The multiplexer is used to route one of multiple input signals to a single output signal. The decoder function, used when the device is in the active state, is designed to accept an 8-bit signal and translate it into one of three distinct output address lines. This device is capable of addressing up to 256Kbits.