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DATA  SHEET

Product specification

File under Integrated Circuits, IC06

December 1990

INTEGRATED CIRCUITS

74HC/HCT147

10-to-4 line priority encoder

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

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December 1990

2

Philips Semiconductors

Product specification

10-to-4 line priority encoder

74HC/HCT147

FEATURES

Encodes 10-line decimal to 4-line BCD

Useful for 10-position switch encoding

Used in code converters and generators

Output capability: standard

I

CC

category: MSI

GENERAL DESCRIPTION

The 74HC/HCT147 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/HCT147 9-input priority encoders accept data

from nine active LOW inputs (A

0

to A

8

) and provide a

binary representation on the four active LOW outputs

(Y

0

to Y

3

). A priority is assigned to each input so that when

two or more inputs are simultaneously active, the input

with the highest priority is represented on the output, with

input line A

8

having the highest priority.

The devices provide the 10-line to 4-line priority encoding

function by use of the implied decimal “zero”. The “zero” is

encoded when all nine data inputs are HIGH, forcing all

four outputs HIGH.

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

µ

W):

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 A

n

to Y

n

C

L

= 15 pF; V

CC

= 5 V

15

17

ns

C

I

input capacitance

3.5

3.5

pF

C

PD

power dissipation capacitance per package

notes 1 and 2

30

33

pF

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December 1990

3

Philips Semiconductors

Product specification

10-to-4 line priority encoder

74HC/HCT147

PIN DESCRIPTION

PIN NO.

SYMBOL

NAME AND FUNCTION

8

GND

ground (0 V)

9, 7, 6, 14

Y

0

to Y

3

BCD address outputs (active LOW)

11, 12, 13, 1, 2, 3, 4, 5, 10

A

0

to A

8

decimal data inputs (active LOW)

15

n.c.

not connected

16

V

CC

positive supply voltage

Fig.1  Pin configuration.

Fig.2  Logic symbol.

Fig.3  IEC logic symbol.

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December 1990

4

Philips Semiconductors

Product specification

10-to-4 line priority encoder

74HC/HCT147

FUNCTION TABLE

Notes

1. H = HIGH voltage level

L = LOW voltage level

X = don’t care

INPUTS

OUTPUTS

A

0

A

1

A

2

A

3

A

4

A

5

A

6

A

7

A

8

Y

3

Y

2

Y

1

Y

0

H

H

H

H

H

H

H

H

H

H

H

H

H

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

L

X

X

L

H

X

L

H

H

L

H

H

H

L

L

H

H

H

H

L

L

H

H

L

L

L

H

L

H

X

X

X

X

X

X

X

L

X

X

L

H

X

L

H

H

L

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

L

L

H

H

H

H

L

L

L

H

L

H

L

H

H

H

H

H

H

H

H

H

H

H

L

Fig.4  Functional diagram.

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December 1990

5

Philips Semiconductors

Product specification

10-to-4 line priority encoder

74HC/HCT147

Fig.5  Logic diagram.

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December 1990

6

Philips Semiconductors

Product specification

10-to-4 line priority encoder

74HC/HCT147

DC CHARACTERISTICS FOR 74HC

For the DC characteristics see

“74HC/HCT/HCU/HCMOS Logic Family Specifications”

.

Output capability: standard

I

CC

category: MSI

AC CHARACTERISTICS FOR 74HC

GND = 0 V; t

r

= t

f

= 6 ns; C

L

= 50 pF

SYMBOL

PARAMETER

T

amb

(

°

C)

UNIT

TEST CONDITIONS

74HC

V

CC

(V)

WAVEFORMS

+

25

40 to

+

85

40 to

+

125

min.

typ.

max.

min.

max.

min.

max.

t

PHL

/ t

PLH

propagation delay

A

n

to Y

n

50

18

14

160

32

27

200

40

34

240

48

41

ns

2.0

4.5

6.0

Fig.6

t

THL

/ t

TLH

output transition

time

19

7

6

75

15

6

95

19

16

110

22

19

ns

2.0

4.5

6.0

Fig.6

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December 1990

7

Philips Semiconductors

Product specification

10-to-4 line priority encoder

74HC/HCT147

DC CHARACTERISTICS FOR 74HCT

For the DC characteristics see

“74HC/HCT/HCU/HCMOS Logic Family Specifications”

.

Output capability: standard

I

CC

category: MSI

Note to HCT types

The value of additional quiescent supply current (

I

CC

) for a unit load of 1 is given in the family specifications.

To determine

I

CC

per input, multiply this value by the unit load coefficient shown in the table below.

AC CHARACTERISTICS FOR 74HCT

GND = 0 V; t

r

= t

f

= 6 ns; C

L

= 50 pF

AC WAVEFORMS

PACKAGE OUTLINES

See

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

.

INPUT

UNIT LOAD COEFFICIENT

A

3

, A

4

, A

7

, A

8

1.50

A

5

, A

6

, A

0

, A

1

, A

2

1.10

SYMBOL

PARAMETER

T

amb

(

°

C)

UNIT

TEST CONDITIONS

74HCT

V

CC

(V)

WAVEFORMS

+

25

40 to

+

85

40 to

+

125

min.

typ.

max.

min.

max.

min.

max.

t

PHL

/ t

PLH

propagation delay

A

n

to Y

n

20

35

44

53

ns

4.5

Fig.6

t

THL

/ t

TLH

output transition

time

7

15

19

22

ns

4.5

Fig.6

Fig.6

Waveforms showing the decimal data inputs (A

n

) to output (Y

n

) propagation delays and the output

transition times.

(1) HC : V

M

= 50%; V

I

= GND to V

CC

.

HCT: V

M

= 1.3 V; V

I

= GND to 3 V.