Datasheet M74HCT138 Datasheet (ST)

M74HCT138

3 TO 8 LINE DECODER (INVERTING)

■ HIGH SPEED:

t

= 16ns (TYP.) at VCC = 4.5V

PD

■ LOW POWER DISSIPATION:

= 4µA(MAX.) at TA=25°C

I

CC

■ COMPA TIBLE WITH TTL OUTPUTS :

V

= 2V (MIN.) VIL = 0.8V (MAX)

IH

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

| = IOL = 4mA (MIN)

OH

■ BALANCED PROPAGATION DELAYS:

t

≅ t

PHL

PLH

■ PIN AND FUNCTION COMPATIBLE WITH

74 SERIES 138

DESCRIPTION

The M74HCT138 is an high 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 o ne of t he out puts will
go low. If enable input G1 is held low or either G2A
or G2B is held high, the decoding function is
inhibited and all the 8 outputs go high. Three

TSSOPDIP SOP

ORDER CODES

PACKAGE TUBE T & R

DIP M74HCT138B1R

SOP M74HCT138M1R M74HCT138RM13TR

TSSOP M74HCT138TTR

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

1/9August 2001

M74HCT138

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
LLHHLLHHHHLHHH
LLHHLHHHHHHLHH
LLHHHLHHHHHHLH
LLHHHHHHHHHHHL

OUTPUTS

LOGIC DIAGRAM

This log i c diagram has not be used to esti m ate propagation delays

2/9

M74HCT138

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

, t

Input Rise and Fall Time (VCC = 4.5 to 5.5V)

f

-0.5 to +7 V

± 20 mA
± 20 mA
± 25 mA
± 50 mA

500(*) mW

-65 to +150 °C

300 °C

4.5 to 5.5 V

CC
CC

-55 to 125 °C
0 to 500 ns

V
V

V
V

DC SPECIFICATIONS

Symbol Parameter

V

V

V

V

I

∆ 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
Additional Worst

CC

Case Supply
Current

Test Condition Value

T

= 25°C

V

CC

(V)

A

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

4.5
to

2.0 2.0 2.0 V

5.5

4.5
to

0.8 0.8 0.8 V

5.5

4.5

4.5

5.5

5.5

IO=-20 µA

I

=-4.0 mA

O

IO=20 µA

I

=4.0 mA

O

= VCC or GND

V

I

V

= VCC or GND

I

5.5 Per Input pin

= 0.5V or

V

I

V

= 2.4V

I

4.4 4.5 4.4 4.4

4.18 4.31 4.13 4.10

0.0 0.1 0.1 0.1

0.17 0.26 0.33 0.40
± 0.1 ± 1 ± 1 µA

2.0 2.9 3.0 mA

Other Inputs at

V

or GND

CC

I

= 0

O

-40 to 85°C -55 to 125°C

Unit

V

V

44080µA

3/9

M74HCT138

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

Test Condition Value

T

Symbol Parameter

t

TLH tTHL

t

PLH tPHL

t

PLH tPHL

t

PLH tPHL

Output Transition
Time

Propagation Delay
Time (A, B, C - Y

Propagation Delay
Time (G1 - Y

Propagation Delay
Time (G2 - Y

V

CC

(V)

4.5 8151922ns

4.5 17 30 38 45 ns

)

)

)

4.5 16 30 38 45 ns

4.5 19 30 38 45 ns

= 25°C

A

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

CAPACITIVE CHARACTERISTICS

Test Condition Value

T

Symbol Parameter

V

CC

(V)

C

C

Input Capacitance

IN

Power Dissipation

PD

Capacitance (note

1)

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 Circ ui t). Averag e operatin g current can be obtained by t he following equation. I

= 25°C

A

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

5101010pF

52 pF

-40 to 85°C -55 to 125°C

-40 to 85°C -55 to 125°C

= CPD x VCC x fIN + ICC

CC(opr)

Unit

Unit

TEST CIRCUIT

CL = 50pF or equivalent (in cludes jig and probe capaci tance)
R

= Z

of pulse generator (typically 50Ω)

T

OUT

4/9

M74HCT138

WAVEFORM 1: PROPAGATION DELAYS FOR INVERTING OUTPUTS (f=1MHz; 50% duty cycle)

WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING OUTPUTS (f = 1 M Hz ; 5 0 % d ut y c y c l e)

5/9

M74HCT138

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

6/9

P001C

SO-16 MECHANICAL DATA

M74HCT138

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

7/9

M74HCT138

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

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1

0080338D

M74HCT138

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systems without express written approval of STMicroelectronics.

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