74HC138 – 3 to 8 Line Decoder

The M74HC138 is a high speed CMOS 3 to 8 line decoder. There are three bina­ry select inputs (A, B, and C) which deter­mine which one of the eight out­puts (Y0-Y7) will go high. This chip has three enable inputs (G1, ~G2A, and ~G2B); when any enable pins are brought low (or high in G1’s case), all out­put pins are pulled low.This is a great tool if you need to increase the num­ber of out­puts on your micr­con­troller. For exam­ple, it’s used in the 3x3x3 LED Cube to help an ATmega168 con­trol the 27 LEDs.This device comes in a 16-pin DIP pack­age.Fea­tures:High speedWide oper­at­ing volt­age range (2 to 8VDC)Low pow­er dis­si­pa­tion (~4µA)High noise immu­ni­tySym­met­ri­cal out­put imped­anceBal­anced prop­a­ga­tion delaysInputs equipped with pro­tec­tion cir­cuits against sta­t­ic dis­charge and tran­sient excess volt­ageDoc­u­ments:DatasheeRelated