Fairchild Semiconductor 74LVX157SJX, 74LVX157SJ, 74LVX157MX, 74LVX157MTCX, 74LVX157MTC Datasheet

May 1993
Revised March 1999

74LVX157 Low Voltage Quad 2-Input Multiplexer

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74LVX157
Low Voltage Quad 2-Input Multiplexer

General Description

The LVX157 is a high-speed quad 2-input multiplexer. Four
bits of data from two sources can be selected using the
common Select and Enable inputs. The four outputs
present the selected data in the true (noninverted) form.
The LVX157 can also be used as a function gener ator.

Features

■ Input voltage level translation from 5V to 3V

■ Ideal for low power/low noise 3.3V applications

■ Guaranteed simultaneous switching noise level and

dynamic threshold performance

Ordering Code:

Devices are also avai lable in Tape and Reel. Specify by append ing letter suffix “X” to the ordering code.

Logic Symbols

IEEE/IEC

Connection Diagram

Pin Descriptions

Order Number Package Number Package Description

74LVX157M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150” Narrow
74LVX157SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74LVX157MTC MTC16 16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

Pin Names Description

I

0a–I0d

Source 0 Data Inputs

I

1a–I1d

Source 1 Data Inputs

E

Enable Input
S Select Input
Z

a–Zd

Outputs

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74LVX157

Truth Table

H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial

Functional Description

The LVX157 is a quad 2-input multiplexer. It selects four
bits of data from two sources un der the control of a com­mon Select input (S). The Enable input (E

) is active-LOW.

When E

is HIGH, all of the outputs (Z) are forced LOW
regardless of all other inputs. The LVX157 is the logic
implementation of a 4-pole, 2-position switch where the
position of the switch is determined by the logic levels sup­plied to the Select input. The logic equations for the outputs
are shown below:

Z

a

= E • (I1a • S + I0a • S)

Z

b

= E • (I

1b

• S + I0b • S)

Z

c

= E • (I

1c

• S + I0c • S)

Z

d

= E • (I

1d

• S + I0d • S)

A common use of the LVX157 is the moving of data from
two groups of registers to four common output busses. The
particular register from which the data comes is determined
by the state of t he S elect in put . A less ob vious us e is as a
function generator. The LVX157 can generate any four of
the sixteen different functions of two variables with one
variable common. This is useful for implementing gating
functions.

Logic Diagram

Inputs Outputs

E

SI0I

1

Z

HXXX L
LHXL L
LHXH H
LLLX L
LLHX H