Datasheet M74HC148 Datasheet (ST)

M74HC148

8 TO 3 LI NE PRIO RITY ENCODER

■ HIGH SPEED:

t

= 16ns (TYP.) at VCC = 6V

PD

■ LOW POWER DISSIPATION:

I

= 4µA(MAX.) at TA=25°C

CC

■ HIGH NOISE IMMUNITY:

V

= V

NIH

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

| = IOL = 4mA (MIN)

OH

■ BALANCED PROPAGATION DELAYS:

t

≅ t

PLH

■ WIDE OPERATING VOLTAGE RANGE:

V

(OPR) = 2V to 6V

CC

■ PIN AND FUNCTION COMPATIBLE WITH

= 28 % VCC (MIN.)

NIL

PHL

74 SERIES 148

DESCRIPTION

The M74HC148 is an hi gh speed CMOS 8 TO 3
LINE PRIORITY ENCODER fabricated with
silicon gate C

2

MOS technology.
The M74HC148 encodes eight data lines to
three-line (4-2-1) binary (octal). Cascading
circuitry (enable input EI and enab le output EO)

TSSOPDIP SOP

ORDER CODES

PACKAGE TUBE T & R

DIP M74HC148B1R

SOP M74HC148M1R M74HC148RM13TR

TSSOP M74HC148TTR

has been provided to allow octal expansion
without the need for external circuitry. Data inputs
are active at the low logic level.
All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.

PIN CONNECTION AND IEC LOGIC SYMBOLS

1/11July 2001

M74HC148

INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION

PIN No SYMBOL NAME AND FUNCTION

9, 7, 6 A

10, 11, 12,

13, 1, 2, 3, 4

15 EO Enable Output

5 EI Enable Input

14 GS Priority Flag Output

8 GND Ground (0V)

16 V

TRUTH TABLE

INPUTS OUTPUTS

E101234567A2A1A0GSE0

HXXXXXXXXHHHHH

LHHHHHHHHHHHHL
LXXXXXXXLLLLLH
LXXXXXXLHLLHLH
LXXXXXLHHLHLLH
LXXXXLHHHLHHLH
LXXXLHHHHHL LLH
LXXLHHHHHHLHLH
LXLHHHHHHHHL LH
LLHHHHHHHHHHLH

X : Don’t Care

to A2Data Outputs

0

0 to 7 Data Inputs

CC

Positive Supply Voltage

LOGIC DIAGRAM

This log i c diagram has not be used to est i m at e propagation delays

2/11

M74HC148

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

I

I

OK

I

I

or I

CC

P

T

T

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
(*) 500mW at 65

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter Value Unit

V

V

V

T

t

r

Supply Voltage

CC

DC Input Voltage -0.5 to VCC + 0.5

I

DC Output Voltage -0.5 to VCC + 0.5

O

DC Input Diode Current

IK

DC Output Diode Current
DC Output Current

O

DC VCC or Ground Current

GND

Power Dissipation

D

Storage Temperature

stg

Lead Temperature (10 sec)

L

°C; derate to 300mW by 10mW/°C from 65°C to 85°C

Supply Voltage

CC

Input Voltage 0 to V

I

Output Voltage 0 to V

O

Operating Temperature

op

Input Rise and Fall Time VCC = 2.0V

, t

f

V
V

CC
CC

= 4.5V
= 6.0V

-0.5 to +7 V

± 20 mA
± 20 mA
± 25 mA
± 50 mA

500(*) mW

-65 to +150 °C

300 °C

2 to 6 V

CC
CC

-55 to 125 °C
0 to 1000 ns

0 to 500 ns
0 to 400 ns

V
V

V
V

3/11

M74HC148

DC SPECIFICATIONS

Symbol Parameter

V

V

V

V

I

High Level Input

IH

Voltage

Low Level Input

IL

Voltage

High Level Output

OH

Voltage

Low Level Output

OL

Voltage

I

Input Leakage

I

Current
Quiescent Supply

CC

Current

Test Condition Value

V

(V)

CC

= 25°C

A

Min. Typ. Max. Min. Max. Min. Max.

-40 to 85°C -55 to 125°C

T

2.0 1.5 1.5 1.5

6.0 4.2 4.2 4.2

2.0 0.5 0.5 0.5

6.0 1.8 1.8 1.8

2.0

4.5

6.0

4.5

6.0

2.0

4.5

6.0

4.5

6.0

6.0

6.0

IO=-20 µA
I

=-20 µA

O

I

=-20 µA

O

I

=-4.0 mA

O

I

=-5.2 mA

O

IO=20 µA
I

=20 µA

O

I

=20 µA

O

I

=4.0 mA

O

I

=5.2 mA

O

= VCC or GND

V

I

= VCC or GND

V

I

1.9 2.0 1.9 1.9

4.4 4.5 4.4 4.4

5.9 6.0 5.9 5.9

4.18 4.31 4.13 4.10

5.68 5.8 5.63 5.60

0.0 0.1 0.1 0.1

0.0 0.1 0.1 0.1

0.0 0.1 0.1 0.1

0.17 0.26 0.33 0.40

0.18 0.26 0.33 0.40
± 0.1 ± 1 ± 1 µA

44080µA

Unit

V4.5 3.15 3.15 3.15

V4.5 1.35 1.35 1.35

V

V

4/11

AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, Input tr = tf = 6ns)

Test Condition Value

T

Symbol Parameter

t

TLH tTHL

t

PLH tPHL

Output Transition
Time

Propagation Delay
Time (In - A0, A1,
A2)

t

PLH tPHL

t

PLH tPHL

t

PLH tPHL

t

PLH tPHL

Propagation Delay
Time (In - EO, GS)

Propagation Delay
Time ( EI -EO)

Propagation Delay
Time (EI -GS)

Propagation Delay
Time (EI - A0, A1,
A2)

V

CC

(V)

2.0 30 75 95 110

6.0 7131619

2.0 60 150 190 225

6.0 16 26 32 38

2.0 60 150 190 225

6.0 16 26 32 38

2.0 40 115 145 175

6.0 12 20 25 30

2.0 40 115 145 175

6.0 12 20 25 30

2.0 40 115 145 175

6.0 12 20 25 30

= 25°C

A

Min. Typ. Max. Min. Max. Min. Max.

M74HC148

-40 to 85°C -55 to 125°C

Unit

ns4.5 8151922

ns4.5 19 30 38 45

ns4.5 19 30 38 45

ns4.5 14 23 29 35

ns4.5 14 23 29 35

ns4.5 14 23 29 35

CAPACITIVE CHARACTERISTICS

Test Condition Value

T

Symbol Parameter

V

CC

(V)

C

C

1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without

load. (R ef er to Test Circui t). Averag e operating current can be obtained by the following equation. I

Input Capacitance

IN

Power Dissipation

PD

Capacitance (note 1)5.0 60 pF

5.0 5101010pF

= 25°C

A

-40 to 85°C -55 to 125°C

Min. Typ. Max. Min. Max. Min. Max.

= CPD x VCC x fIN + ICC

CC(opr)

Unit

5/11

M74HC148

TEST CIRCUIT

CL = 50pF or equivalent (includes jig and p robe capacit ance)
R

= Z

of pulse generator (typically 50Ω)

T

OUT

WAVEFORM 1: PROPAGATION DELAY TIMES ,FOR INVERTING AND NON INVERTING OUTPUTS
(f=1MHz; 50% duty cycle)

6/11

TYPICAL APPLICATION

M74HC148

7/11

M74HC148

Plastic DIP-16 (0.25) MECHANICAL DATA

mm. inch

DIM.

MIN. TYP MAX. MIN. TYP. MAX.

a1 0.51 0.020

B 0.77 1.65 0.030 0.065
b 0.5 0.020

b1 0.25 0.010

D 20 0.787
E 8.5 0.335

e 2.54 0.100

e3 17.78 0.700

F 7.1 0.280

I 5.1 0.201

L 3.3 0.130

Z 1.27 0.050

8/11

P001C

SO-16 MECHANICAL DATA

M74HC148

DIM.

A 1.75 0.068
a1 0.1 0.2 0.003 0.007
a2 1.65 0.064

b 0.35 0.46 0.013 0.018

b1 0.19 0.25 0.007 0.010

C 0.5 0.019
c1 45° (typ.)

D 9.8 10 0.385 0.393

E 5.8 6.2 0.228 0.244

e 1.27 0.050

e3 8.89 0.350

F 3.8 4.0 0.149 0.157

G 4.6 5.3 0.181 0.208

L 0.5 1.27 0.019 0.050

M 0.62 0.024

S8° (max.)

MIN. TYP MAX. MIN. TYP. MAX.

mm. inch

PO13H

9/11

M74HC148

TSSOP16 MECHANICAL DATA

mm. inch

DIM.

MIN. TYP MAX. MIN. TYP. MAX.

A 1.2 0.047

A1 0.05 0.15 0.002 0.004 0.006

A2 0.8 1 1.05 0.031 0.039 0.041

b 0.19 0.30 0.007 0.012

c 0.09 0.20 0.004 0.0089

D 4.9 5 5.1 0.193 0.197 0.201

E 6.2 6.4 6.6 0.244 0.252 0.260

E1 4.3 4.4 4.48 0.169 0.173 0.176

e 0.65 BSC 0.0256 BSC

K0° 8°0° 8°

L 0.45 0.60 0.75 0.018 0.024 0.030

A2

A

A1

b

e

c

K

L

E

D

E1

PIN 1 IDENTIFICATION

10/11

1

0080338D

M74HC148

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