Philips 74HCT157U, 74HCT157PW, 74HCT157N, 74HCT157DB, 74HC157U Datasheet

DATA SH EET

Product specification

File under Integrated Circuits, IC06

December 1990

INTEGRATED CIRCUITS

74HC/HCT157

Quad 2-input multiplexer

For a complete data sheet, please also download:

•The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications

•The IC06 74HC/HCT/HCU/HCMOS Logic Package Information

•The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines

December 1990 2

Philips Semiconductors Product specification

Quad 2-input multiplexer 74HC/HCT157

FEATURES

• Non-inverting data path

• Output capability: standard

• I

CC

category: MSI

GENERAL DESCRIPTION

The 74HC/HCT157 are high-speed Si-gate CMOS devices

and are pin compatible with low power Schottky TTL

(LSTTL). They are specified in compliance with JEDEC

standard no. 7A.

The 74HC/HCT157 are quad 2-input multiplexers which

select 4 bits of data from two sources under the control of

a common data select input (S). The four outputs present

the selected data in the true (non-inverted) form. The

enable input (

E) is active LOW. When E is HIGH, all of the

outputs (1Y to 4Y) are forced LOW regardless of all other

input conditions.

Moving the data from two groups of registers to four

common output buses is a common use of the “157”. The

state of the common data select input (S) determines the

particular register from which the data comes. It can also

be used as function generator.

The device is useful for implementing highly irregular logic

by generating any four of the 16 different functions of two

variables with one variable common.

The “157” is the logic implementation of a 4-pole,

2-position switch, where the position of the switch is

determined by the logic levels applied to S.

The logic equations are:

1Y = E.(1l

1

.S + 1l

0

.S)

2Y = E.(2l

1

.S + 2l

0

.S)

3Y = E.(3l

1

.S + 3l

0

.S)

4Y = E.(4l

1

.S + 4l

0

.S)

The “157” is identical to the “158” but has non-inverting

(true) outputs.

QUICK REFERENCE DATA

GND = 0 V; T

amb

= 25 °C; t

r

= t

f

= 6 ns

Notes

1. C

PD

is used to determine the dynamic power dissipation (P

D

in µW):

P

D

= C

PD

× V

CC

2

× f

i

+ ∑ (C

L

× V

CC

2

× f

o

) where:

f

i

= input frequency in MHz

f

o

= output frequency in MHz

∑ (C

L

× V

CC

2

× f

o

) = sum of outputs

C

L

= output load capacitance in pF

V

CC

= supply voltage in V

2. For HC the condition is V

I

= GND to V

CC

For HCT the condition is V

I

= GND to V

CC

− 1.5 V

ORDERING INFORMATION

See

“74HC/HCT/HCU/HCMOS Logic Package Information”

.

SYMBOL PARAMETER CONDITIONS

TYPICAL

UNIT

HC HCT

t

PHL

/ t

PLH

propagation delay C

L

= 15 pF; V

CC

= 5 V

nI

0

, nI

1

to nY 11 13 ns

E to nY 11 12 ns

S to nY 12 19 ns

C

I

input capacitance 3.5 3.5 pF

C

PD

power dissipation capacitance per multiplexer notes 1 and 2 70 70 pF

December 1990 3

Philips Semiconductors Product specification

Quad 2-input multiplexer 74HC/HCT157

PIN DESCRIPTION

PIN NO. SYMBOL NAME AND FUNCTION

1 S common data select input

2, 5, 11, 14 1I

0

to 4I

0

data inputs from source 0

3, 6, 10, 13 1I

1

to 4I

1

data inputs from source 1

4, 7, 9, 12 1Y to 4Y multiplexer outputs

8 GND ground (0 V)

15

E enable input (active LOW)

16 V

CC

positive supply voltage

Fig.1 Pin configuration. Fig.2 Logic symbol. Fig.3 IEC logic symbol.