SGS Thomson Microelectronics M74HC148 Datasheet

8 TO 3 LINE PRIORITY ENCODER

.HIGH SPEED

tPD= 15 ns(TYP.) AT VCC=5V

.LOWPOWERDISSIPATION

ICC=4µA(MAX.) AT TA=25°C

.HIGH NOISEIMMUNITY

V

NIH=VNIL

=28%VCC(MIN.)

.OUTPUT DRIVE CAPABILITY

10 LSTTL LOADS

.SYMMETRICALOUTPUT IMPEDANCE

IOH =IOL= 4 mA(MIN.)

.BALANCEDPROPAGATION DELAYS

t

PLH=tPHL

.WIDE OPERATINGVOLTAGE RANGE

VCC(OPR)= 2V TO 6 V

.PIN ANDFUNCTION COMPATIBLE

WITH 54/74LS148

DESCRIPTION

The M54/74HC148 is a high speedCMOS 8-TO-3
LINE PRIORITY ENCODER fabricated in silicon
gate C2MOStechnology.

It hasthesame high speedperformance for LSTTL
combined withtrue CMOSlowpower consumption.
The M54/74HC148 encodes eight data lines to
three-line (4-2-1) binary (octal). Cascading circuitry
(enable input EI and enable output EO) has been
provided to allow octal expansion without the need
for external circuitry. Data inputs are active at the
low logiclevel.

All inputs are equipped with protection circuits
against static discharge and transient excess volt­age.

M54HC148
M74HC148

B1R

(PlasticPackage)

M1R

(MicroPackage)

ORDER CODES :

M54HC 148F1R M74H C148M1R
M74HC 148B1R M74HC1 48C1R

PIN CONNECTIONS(top view)

F1R

(CeramicPackage)

C1R

(Chip Carrier)

INPUT AND OUTPUT EQUIVALENT CIRCUIT

October 1992

NC =
No Internal
Connection

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M54/M74HC148

TRUTH TABLE

INPUTS OUTPUTS

E101234567A2A1A0GSE0

HXXXXXXXXHHHHH

LHHHHHHHHHHHHL
LXXXXXXXLLLLLH
LXXXXXXLHLLHLH
LXXXXXLHHLHLLH
LXXXXLHHHLHHLH
LXXXLHHHHHL L LH
LXXLHHHHHHLLHLH
LXLHHHHHHHHLLH
LLHHHHHHHHHHLH

X:Don’t Care

LOGI C DIAGRAM

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M54/M74HC148

PIN DESCRIPTION

IEC LOGIC SYMBOL

PIN No SYMBOL NAME AND FUNCTION

9, 7, 6 A0 to A2 Data Outputs

11, 12, 13,

0 to 7 Data Inputs

1, 2, 3, 4,

10
15 EO Enable Output

5 EI Enable Input

14 GS Priority Flag Output

8 GND Ground (0V)

16 V

CC

Positive Supply Voltage

ABSOLU TE MAXIMU M RAT INGS

Symbol Parameter Value Unit

V

CC

V

V

O

I

IK

I

OK

I

O

I

or I

CC

P

D

T

stg

T

AbsoluteMaximumRatingsarethose values beyondwhichdamage tothedevicemayoccur. Functionaloperationunder these conditionisnotimplied.
(*)500 mW: ≅ 65oC derateto300mWby 10mW/oC: 65oCto85oC

Supply Voltage -0.5 to +7 V
DC Input Voltage -0.5 to VCC+ 0.5 V

I

DC Output Voltage -0.5 to VCC+ 0.5 V
DC Input Diode Current ± 20 mA
DC Output Diode Current ± 20 mA
DC Output Source Sink Current Per Output Pin ± 25 mA
DC VCCor Ground Current ± 50 mA

GND

Power Dissipation 500 (*) mW
Storage Temperature -65 to +150
Lead Temperature (10 sec) 300

L

o

C

o

C

RECO MM ENDED OPERATIN G C ONDI TI O NS

Symbol Parameter Value Unit

V

T

t

V

V

r,tf

Supply Voltage 2 to 6 V

CC

Input Voltage 0 to V

I

Output Voltage 0 to V

O

Operating Temperature: M54HC Series

op

M74HC Series

CC
CC

-55 to +125

-40 to +85

Input Rise and Fall Time VCC= 2 V 0 to 1000 ns

V

= 4.5 V 0 to 500

CC

V

= 6 V 0 to 400

CC

V
V

o

C

o

C

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M54/M74HC148

DC SPECIFICATIO NS

Symbol Parameter

V

V

V

V

I

High Level Input

IH

Voltage

Low Level Input

IL

Voltage

High Level

OH

Output Voltage

Low Level Output

OL

Voltage

I

Input Leakage

I

Current
Quiescent Supply

CC

Current

Test Conditions Value

V

(V)

CC

=25oC

A

54HC and 74HC

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

-40 to 85oC
74HC

-55 to 125oC
54HC

Unit

T

2.0 1.5 1.5 1.5

4.5 3.15 3.15 3.15

6.0 4.2 4.2 4.2

2.0 0.5 0.5 0.5

4.5 1.35 1.35 1.35

6.0 1.8 1.8 1.8

2.0

4.5 4.4 4.5 4.4 4.4

6.0 5.9 6.0 5.9 5.9

4.5 I

6.0 I

2.0

4.5 0.0 0.1 0.1 0.1

6.0 0.0 0.1 0.1 0.1

4.5 I

6.0 I

6.0

=

V

I

IO=-20 µA

V

IH

or

V

IL

=-4.0 mA 4.18 4.31 4.13 4.10

O

=-5.2 mA 5.68 5.8 5.63 5.60

O

V

=

I

IO=20µA

V

IH

or

V

IL

= 4.0 mA 0.17 0.26 0.33 0.40

O

= 5.2 mA 0.18 0.26 0.33 0.40

O

VI=VCCor GND ±0.1 ±1 ±1 µA

1.9 2.0 1.9 1.9

0.0 0.1 0.1 0.1

6.0 VI=VCCor GND 4 40 80 µA

V

V

V

V

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