MC74HC157 ONSEMI [ON Semiconductor], MC74HC157 Datasheet - Page 4

• Manufacturer Part Number: MC74HC157
• Description: Quad 2-Input Data Selectors/Multiplexers
• Manufacturer: ONSEMI [ON Semiconductor]

INPUTS
A0, A1, A2, A3 (Pins 2, 5, 11, 14)
transferred to the outputs when the Select input is at a low
level and the Output Enable input is at a low level. The data
is presented to the outputs in noninverted form.
B0, B1, B2, B3 (Pins 3, 6, 10, 13)
transferred to the outputs when the Select input is at a high
level and the Output Enable input is at a low level. The data
is presented to the outputs in noninverted form.
OUTPUTS
Y0, Y1, Y2, Y3 (Pins 4, 7, 9, 12)
these outputs when the Output Enable input is at a low level.
Nibble A inputs. The data present on these pins is
Nibble B inputs. The data present on these pins is
Data outputs. The selected input Nibble is presented at
INPUT A OR B
OUTPUT Y
t PLH
t r
t TLH
10%
Figure 1. HC157A
50%
10%
50%
90%
90%
OUTPUT Y
OUTPUT
ENABLE
t PHL
t f
*Includes all probe and jig capacitance
SWITCHING WAVEFORMS
t THL
t PHL
t THL
PIN DESCRIPTIONS
DEVICE
Figure 4. Test Circuit
UNDER
http://onsemi.com
TEST
MC74HC157A
10%
Figure 3. HC157A
50%
GND
V CC
90%
90%
50%
t r
10%
4
OUTPUT
The data present on these pins is in its noninverted form. For
the Output Enable input at a high level, the outputs are at a
low level.
CONTROL INPUTS
Select (Pin 1)
transferred to the outputs. A low level on this input selects
the A inputs and a high level selects the B inputs.
Output Enable (Pin 15)
selected input data to be presented at the outputs. A high
level on this input sets all outputs to a low level.
Nibble select. This input determines the data word to be
Output Enable input. A low level on this input allows the
TEST POINT
SELECT
OUTPUT Y
t f
C L *
Figure 2. Y versus Select, Noninverted
t PLH
t PLH
t TLH
t r
t TLH
V CC
GND
10%
50%
10%
90%
50%
90%
t f
t PHL
t THL
GND
V CC