Datasheet 74AC138 Datasheet (SGS Thomson Microelectronics)

74AC138

3 TO 8 LINE DECODER (INVERTING)

■ HIGH SPEED: t

■ LOWPOWERDISSIPATION:

=8µA (MAX.)at TA=25oC

I

CC

■ HIGH NOISE IMMUNITY:

V

NIH=VNIL

■ 50Ω TRANSMISSION LINE DRIVING

=4.5 ns (TYP.) at VCC=5V

PD

=28%VCC(MIN.)

CAPABILITY

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

|=IOL=24 mA (MIN)

OH

■ BALANCE DPROPAGATIONDELAYS:

t

≅ t

PLH

PHL

■ OPERATINGVOLTAGERAN GE:

V

(OPR) = 2V to 6V

CC

■ PIN AND FUNCTION COMPATIBLE WITH

74SERIES138

■ IMPROVED LATCH-UP IMMUNITY

DESCRIPTION

The AC138 is an advanced high-speed CMOS 3
TO 8 LINE DECODER (INVERTING) fabricated
with sub-micron silicon gate and double-layer
metal wiring C

2

MOS technology.

If the device is enabled, 3 binary select inputs (A,
B and C) determine which one of the outputs will

B

(Plastic Package)

(Micro Package)

M

ORDERCODES:

74AC138B

go low. If enable input G1 is held low or either
G2A or G2B is held high, the decoding function is
inhibitedand all the 8 outputsgoto high.

Tree enable inputs are provided to ease cascade
connection and application of address decoders
for memory systems.

It is ideal for low power applications mantaining
high speed operation similar to equivalent Bipolar
SchottkyTTL.

All inputs and outputs are equipped with
protectioncircuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.

PINCONNECTION AND IEC LOGIC SYMBOLS

April 1997

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74AC138

INPUTAND OUTPUTEQUIVALENTCIRCUIT

PIN DESCRIPTION

PI N No SYM B O L NAME A ND FUNCT I ON

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

4, 5 G2A, G2B Enable Inputs

6 G1 Enable Input

15, 14, 13,
12, 11, 10,

9, 7

8 GND Ground (0V)

16 V

Y0 to Y7 Outputs

CC

Positive Supply Voltage

TRUTH TABLE

INPUTS OUTPUTS

ENABLE SELEC T

G2B G2A G1 C B A Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7

XXLXXXHHHHHHHH
XHXXXXHHHHHHHH
HXXXXXHHHHHHHH
LLHLL LLHHHHHHH
LLHLLHHLHHHHHH
LLHLHLHHLHHHHH
LLHLHHHHHLHHHH
LLHHL LHHHHLHHH
LLHHLHHHHHHLHH
LLHHHLHHHHHHLH
LLHHHHHHHHHHHL

X:Don’t Care

LOGICDIAGRAM

This logic diagram has not be used to estimate propagation delays

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74AC138

ABSOLUTE MAXIMUMRATINGS

Symb o l Parame t er Val u e Uni t

V

V

V

I

I

OK

I

orI

I

CC

T

T

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.

RECOMMENDED OPERATINGCONDITIONS

Symb o l Parame t er Value Un i t

V

V

V

T

dt/dv Input Rise and Fall Time V

1) VINfrom30% to70%ofV

Supply Voltage -0.5 to +7 V

CC

DC Input Voltage -0.5 to VCC+ 0.5 V

I

DC Output Voltage -0.5 to VCC+ 0.5 V

O

DC Input Diode Current ± 20 mA

IK

DC Output Diode Current ± 20 mA
DC Output Current ± 50 mA

O

DC VCCor Ground Current ± 400 mA

GND

Storage Temperature -65 to +150

stg

Lead Temperature (10 sec) 300

L

Supply Voltage 2 to 6 V

CC

Input Voltage 0 to V

I

Output Voltage 0 to V

O

Operating Temperature: -40 to +85

op

= 3.0, 4.5 or 5.5 V(note 1) 8 ns/V

CC

CC

CC
CC

o

C

o

C

V
V

o

C

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74AC138

DC SPECIFICATIONS

Symbol Parameter Test Condit ions Value Unit

V

CC

(V)

High Level Input Voltage 3.0 VO= 0.1 V or

V

IH

4.5 3.15 2.25 3.15

V

CC

- 0.1 V

T

=25oC-40to85

A

Min. Typ. Ma x. Min. Max.

2.1 1.5 2.1

o

C

5.5 3.85 2.75 3.85

Low Level Input Voltage 3.0 VO= 0.1 V or

V

IL

4.5 2.25 1.35 1.35

V

CC

- 0.1 V

1.5 0.9 0.9

5.5 2.75 1.65 1.65

High Level Output

V

OH

Voltage

Low Level Output

V

OL

Voltage

Input Leakage Current

I

I

Quiescent Supply

I

CC

3.0

4.5 I

5.5 I

V
V

3.0 I

4.5 I

5.5 I

3.0

4.5 I

5.5 I

V
V

3.0 I

4.5 I

5.5 I

5.5

IO=-50 µA 2.9 2.99 2.9

(*)

I
IH

V

IL

=-50 µA 4.4 4.49 4.4

O

=

=-50 µA 5.4 5.49 5.4

or

O

=-12 mA 2.56 2.46

O

=-24 mA 3.86 3.76

O

=-24 mA 4.86 4.76

O

IO=50 µA 0.002 0.1 0.1

(*)

I
IH

V

IL

=50 µA 0.001 0.1 0.1

O

=

=50 µA 0.001 0.1 0.1

or

O

=12 mA 0.36 0.44

O

=24 mA 0.36 0.44

O

=24 mA 0.36 0.44

O

VI=VCCor GND ±0.1 ±1 µA

5.5 VI=VCCor GND 8 80 µA

Current
Dynamic Output Current

I

OLD

OHD

(note 1, 2)

I

1) Maximum test duration 2ms, one output loaded at time

2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50 Ω.
(*)All outputs loaded.

5.5 V

= 1.65 V max 75 mA

OLD

V

= 3.85 V min -75 mA

OHD

V

V

V

V

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AC ELECTRICAL CHARACTERISTICS (CL= 50 pF, RL=500 Ω, Inputtr=tf=3ns)

74AC138

Symbol Parame ter Test Cond itio n Value Unit

o

C

ns

ns

ns

t

Propagation Delay Time

PLH

t

A,B,C to Y

PHL

Propagation Delay Time

t

PLH

t

G1to Y

PHL

Propagation Delay Time

t

PLH

t

G2A or G2B to Y

PHL

(*) Voltagerangeis3.3V± 0.3V
(**) Voltagerange is5V± 0.5V

V

3.3

5.0

3.3

5.0

3.3

5.0

(V)

CC

(**)

(**)

(**)

T

=25oC-40to85

A

Min. Typ. Ma x. Min. Max.

(*)

1.5 5.5 13 1.5 14

1.5 4.5 9 1.5 10

(*)

1.5 6 13 1.5 14

1.5 4.5 11 1.5 12

(*)

1.5 5.5 13 1.5 14

1.5 4.5 9 1.5 10

CAPACITIVE CHARACTERISTICS

Symbol Parameter Test Condit ions Value Unit

=25oC-40to85

T

A

Min. Typ. Ma x. Min. Max.

4

Input Capacitance

C

IN

Power Dissipation

C

PD

V

CC

(V)

5.0

5.0 60 pF

Capacitance (note 1)

1) CPDis defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load. (Refer to
Test Circuit). Average operating current can be obtained by the following equation. I

(opr)=CPD• VCC•fIN+ICC/n (percircuit)

CC

o

C

pF

TEST CIRCUIT

CL= 50 pF or equivalent (includes jig and probe capacitance)
R

= 500Ω or equivalent

L=R1

R

of pulse generator (typically 50Ω)

T=ZOUT

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74AC138

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

WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING OUTPUTS (f=1MHz; 50%duty cycle)

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Plastic DIP16 (0.25) MECHANICAL DATA

74AC138

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

mm inch

P001C

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74AC138

SO16 MECHANICAL DATA

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 1.75 0.068

a1 0.1 0.2 0.004 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

S 8 (max.)

mm inch

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P013H

74AC138

Information furnishedis believed to be accurate and reliable. However,SGS-THOMSON Microelectronics assumesno responsability for the
consequencesof use ofsuch informationnor for any infringement of patentsorotherrights of third parties whichmayresultsfrom its use. No
licenseisgrantedby implicationor otherwise underany patentorpatent rightsofSGS-THOMSONMicroelectronics.Specifications mentioned
in this publicationare subjecttochange withoutnotice.This publication supersedes and replaces all informationpreviously supplied.
SGS-THOMSONMicroelectronics productsare notauthorizedforuseascriticalcomponents in lifesupportdevicesor systemswithoutexpress
writtenapproval of SGS-THOMSON Microelectonics.

 1997 SGS-THOMSONMicroelectronics- Printedin Italy - All Rights Reserved

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