The 74F138 54F138 1-of-8 Decoder/Demultiplexer is a high-speed 1-of-8 decoder/demultiplexer produced by National Semiconductor Corporation. This device is ideally suited for high-speed bipolar memory chip select address decoding. Multiple input enables allow parallel expansion to a 1-of-24 decoder using just three 'F138 devices or a 1-of-32 decoder using four 'F138 devices and one inverter.