HD74HC157

HD74HC157/HD74HC158 Quad. 2-to-1-line Data Selectors/Multiplexers (with noninverted outputs) Quad. 2-to-1-line Data Selectors/Multiplexers (with inverted outputs) Description These devices each consist of four 2-input digital multiplexers with common select and strobe inputs. On the HD74HC157, when the strobe input is at logical “L” the four outputs assume the values as selected from the inputs. When the strobe input is at a logical “H” the outputs assume logical “L”. The HD74HC158 operates in the same manner, except that its outputs are inverted. Select decoding is done internally resulting in a single select input only. If enabled, the select input determines whether the A or B inputs get routed to their corresponding Y outputs. Features High Speed Operation: tpd (Data to Output) = 12 ns typ (CL = 50 pF) High Output Current: Fanout of 10 LSTTL Loads Wide Operating Voltage: VCC = 2 to 6 V Low Input Current: 1 µA max Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C) Function Table Inputs Strobe H L L L L Select X L L H H A X L H X X B X X X L H Output Y HC157 L L H L H HC158 H H L H L HD74HC157/HD74HC158 Pin Arrangement Select 1 1A 2 Inputs 1B 3 Output 1Y 4 2A 5 2B 6 Output 2Y 7 GND 8 (Top view) 1B 1Y 2A 2B 2Y 4A 4B 4Y 3A 3Y 3B 1A S S 16 VCC 15 Strobe 14 4A Inputs 13 4B 12 4Y 11 3A Inputs 10 3B 9 3Y Output Output Inputs Logic Diagram HD74HC157 1A 1B 2A 2B 3A 3B 4A 4B Select 4Y 3Y 1Y 2Y Strobe 2 HD74HC157/HD74HC158 HD74HC158 1A 1B 2A 2B ...