SGS Thomson Microelectronics 74ACT138 Datasheet

74ACT138

3 TO 8 LINE DECODER (INVERTING)

■ HIGH SPEED: t

■ LOWPOWERDISSIPATION:

=8µA (MAX.)at TA=25oC

I

CC

■ COMPATIBLEWITH TTL OUTPUTS

V

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

IH

■ 50Ω TRANSMISSIONLINE DRIVING

=5 ns (TYP.) atVCC=5V

PD

CAPABILITY

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

|=IOL=24 mA (MIN)

OH

■ BALANCED PROPAGATION DELAYS:

t

≅ t

PLH

PHL

■ OPERATINGVOLTAGERANGE:

V

(OPR)= 4.5V to 5.5V

CC

■ PIN AND FUNCTION COMPATIBLE WITH

74SERIES138

■ IMPROVED LATCH-UP IMMUNITY

DESCRIPTION

The ACT138 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
go low. If enable input G1 is held low or either
G2Aor G2G is held high, the decodingfunctionis
inhibitedand all the 8 outputs go to high.

B

(Plastic Package)

(Micro Package)

M

ORDERCODES:

74ACT138B

Three enable inputs are provided to ease
cascade connection and application of address
decodersfor memory systems.

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

The device is designed to interface directly High
Speed CMOS systems with TTL, NMOS and
CMOSoutput voltage levels.

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

1/8

74ACT138

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

LOGICDIAGRAMS

This logic diagram has not be used to estimate propagation delays

2/8

74ACT138

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

Symbol Parameter Valu e Unit

V

V

V

T

dt/dv Input Rise and Fall Time V

1) VINfrom0.8V to2.0 V

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 4.5 to 5.5 V

CC

Input Voltage 0 to V

I

Output Voltage 0 to V

O

Operating Temperature: -40to +85

op

= 4.5 to 5.5V (note 1) 8 ns/V

CC

CC
CC

o

C

o

C

V
V

o

C

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