SN74LS138 Datasheet - ON Semiconductor

SN74LS138 1-of-8 Decoder/Demultiplexer

SN74LS138 1 of 8 Decoder/ Demultiplexer The LSTTL/MSI SN74LS138 is a high speed 1-of-8 Decoder/ Demultiplexer. This device is ideally suited for high speed bipolar memory chip select address decoding. The multiple input enables allow parallel expansion to a 1-of-24 decoder using just three LS138 devices or to a 1-of-32 decoder using four LS138s and one inverter. The LS138 is fabricated with the Schottky barrier diode process for high speed and is completely compatible with all O.

SN74LS138 Features

* three Enable inputs, two active LOW (E1, E2) and one active HIGH (E3). All outputs will be HIGH unless E1 and E2 are LOW and E3 is HIGH. This multiple enable function allows easy parallel expansion of the device to a 1-of-32 (5 lines to 32 lines) decoder with just four LS138s and one inverter. (See

SN74LS138_ONSemiconductor.pdf