74139 Dual 2-to-4 Line Decoder / Demultiplexer IC
The 74139 is a dual 2 – 4 line decoder with a demultiplexer in the 7400 series. Each side of the IC is a decoder with an active low enable from a 2-bit address to four active low signals. The two decoders can be wired independently, or a /Y from one decoder can be wired to the /E on the other to calculate more complex combinational logic functions.
Specifications:
Parameter Value Unit Propagation delay, nAn to nYn 11 (74HC)
13 (74HCT)ns Propagation delay, nE to nYn 10 (74HC)
13 (74HCT)ns Pin Description :
Pin Symbol Description 1 1E enable input (active low) 2 1A0 address input 3 1A1 address input 4 1Y0 output (active low) 5 1Y1 output (active low) 6 1Y2 output (active low) 7 1Y3 output (active low) 8 GND ground 9 2Y3 output (active low) 10 2Y2 output (active low) 11 2Y1 output (active low) 12 2Y0 output (active low) 13 2A1 address input 14 2A0 address input 15 2E enable input (active low) 16 Vcc supply voltage