54ACT139 Datasheet | National Semiconductor

Description The ’AC/’ACT139 is a high-speed, dual 1-of-4 decoder/ demultiplexer. The device has two independent decoders, each accepting two inputs and providing four mutually-exclusive active-LOW outputs. Each decoder has an active-LOW Enable input which can be used as a data input for a 4-output demultiplexer. Each half of the ’AC/ ’ACT139 can be used as a function generator providing all four minterms of two variables. n n n n n n Multifunction capability Two pletely independent 1-of-4 decoders Active LOW mutually exclusive outputs Outputs source/sink 24 m A ’ACT139 has TTL-patible inputs Standard Military Drawing (SMD) - ’AC139: 5962-87623 - ’ACT139: 5962-87553 Features n ICC reduced by 50% Logic Symbols IEEE/IEC DS100269-8 DS100269-2 Pin Names A0, A1 E O0- O3 Description Address Inputs Enable Inputs Outputs DS100269-1 FACT ® is a registered trademark of Fairchild Semiconductor Corporation. © 1998 National Semiconductor Corporation DS100269 .national. Connection Diagrams Pin Assignment for DIP and Flatpak can be used as the data input for a 4-output demultiplexer application. Each half of the ’AC/’ACT139 generates all four minterms of two variables. These four minterms are useful in some applications, replacing multiple gate functions as shown in , and thereby reducing the number of packages required in a logic network. DS100269-3 Pin Assignment for LCC DS100269-6 FIGURE 1. Gate Functions (Each Half) Truth Table Inputs DS100269-4 Outputs A1 X L L H H O0 H L H H H O1 H H L H H O2 H H H L H O3 H H H H L E H L L L L A0 X L H L H Functional Description The ’AC/’ACT139 is a high-speed dual 1-of-4 decoder/ demultiplexer. The device has two independent decoders, each of which accepts two binary weighted inputs (A0- A1) and provides four mutually exclusive active-LOW outputs (O0- O3). Each decoder has an active-LOW enable (E). When E is HIGH all outputs are forced HIGH. The enable H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial .national....