These devices each consist of four 2-input digital multiplexers with common select and strobe inputs - Hitachi Semiconductor
Description
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 3A 3B 4A 4B Select 4Y 3Y 1Y
2Y
Strobe
3
HD74HC157/HD74HC158
DC Characteristics
Ta = 25°C Item Input voltage Symbol VIH Ta = –40 to +85°C Max — — — 0.
5 1.
35 1.
8 — — — — — 0.
1 0.
1 0.
1 0.
33 0.
33 ±1.
0 40 µA µA I OL = 4 mA I OL = 5.
2 mA Vin = VCC or GND Vin = VCC or GND, Iout = 0 µA V I OH = –4 mA I OH = –5.
2 mA Vin = VIH or VIL I OL = 20 µA V Vin = VIH or VIL I OH = –20 µA V Unit V Test Conditions
VCC (V) Min Typ Max Min 2.
0 4.
5 6.
0 1.
5 — 3.
15 — 4.
2 — — — — — — — — — — 0.
5 1.
5 3.
15 4.
2 —
VIL
...
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