STMicroelectronics M74HC138 User Manual

M74HC138

3 TO 8 LINE DECODER (INVERTING)

■ HIGH SPEED:

t

= 13ns (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 138

DESCRIPTION

The M74HC138 is an hi gh speed CMOS 3 TO 8
LINE DECODER fabricated with silicon gate

2

C

MOS technology.
If the device is enabled, 3 binary select inputs (A,
B, and C) determine which one of the outputs wil l
go low. If enable input G1 is held low or either G2A
or G2B is held high, the decoding function is

TSSOPDIP SOP

ORDER CODES

PACKAGE TUBE T & R

DIP M74HC138B1R

SOP M74HC138M1R M74HC138RM13TR

TSSOP M74HC138TTR

inhibited and all the 8 outputs go high. Three
enable inputs are provided to ease cascade
connection and application of address decoders
for memory systems.
All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.

PIN CONNECTION AND IEC LOGIC SYMBOLS

1/10July 2001

M74HC138

INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION

PIN No SYMBOL NAME AND FUNCTION

1, 2, 3 A, B, C Address Inputs

4, 5 G2A

6 G1 Enable Input

9, 10, 11, 12,

13, 14, 15,

7
8 GND Ground (0V)

16 V

TRUTH TABLE

, G2B Enable Inputs

to Y7 Data Outputs

Y0

CC

Positive Supply Voltage

INPUTS

ENABLE SELECT

G2B

X : Don’t Care

G2A G1CBAY0Y1 Y2 Y3 Y4 Y5 Y6 Y7

XXLXXXHHHHHHHH
XHXXXXHHHHHHHH
HXXXXXHHHHHHHH

LLHLLLLHHHHHHH
LLHLLHHLHHHHHH
LLHLHLHHLHHHHH
LLHLHHHHHLHHHH
LLHHL LHHHHLHHH
LLHHLHHHHHHLHH
LLHHHLHHHHHHLH
LLHHHHHHHHHHHL

OUTPUTS

LOGIC DIAGRAM

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

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M74HC138

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

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