SGS Thomson Microelectronics 74AC240 Datasheet

74AC240

OCTAL BUS BUFFER

WITH 3 STATE OUTPUTS (INVERTED)

■ HIGH SPEED: t

■ LOWPOWERDISSIPATION:

=8µA (MAX.)at TA=25oC

I

CC

■ HIGH NOISE IMMUNITY:

V

NIH=VNIL

■ 50Ω TRANSMISSION LINE DRIVING

=4 ns (TYP.)atVCC=5V

PD

=28%VCC(MIN.)

CAPABILITY

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

|=IOL=24mA(MIN)

OH

■ BALANCE DPROPAGATIONDELAYS:

t

≅ t

PLH

PHL

■ OPERATINGVOLTAGERAN GE:

V

(OPR) = 2V to 6V

CC

■ PIN AND FUNCTION COMPATIBLE WITH

74SERIES240

■ IMPROVED LATCH-UP IMMUNITY

DESCRIPTION

The AC240 is an advanced CMOS OCTAL BUS
BUFFER (3-STATE) fabricated with sub-micron
silicon gate and double-layermetal wiring C

2

MOS

technology. It is ideal for low power applications

B

(Plastic Package)

(Micro Package)

M

ORDERCODES:

74AC240B 74AC240M

mantaining high speed operation similar to
equivalentBipolarSchottky TTL.
G controloutput governs four BUS BUFFERs.

This device is designed to be used with 3 state
memoryaddress drivers,etc.
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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74AC240

INPUTAND OUTPUTEQUIVALENTCIRCUIT

TRUTH TABLE

INPUT OUTPUT

GAnYn

LLH
LHL

HXZ

X:”H”or ”L”
Z: High impedance

PIN DESCRIPTION

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

1 1G Output Enable Input
2,4, 6,8 1A1to1A4 Data Inputs
9,7, 5,3 2Y1to2Y4 Data Outputs

11,13,15, 17 2A1to2A4 Data Inputs
18,16,14, 12 1Y1to1Y4 Data Outputs

19 2G Output Enabel Input
10 GND Ground (0V)
20 V

CC

Positive Supply Voltage

ABSOLUTE MAXIMUM RATINGS

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.

Supply Voltage -0.5to+7 V

CC

DC Input Voltage -0.5toVCC+0.5 V

I

DC Output Voltage -0.5toVCC+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 -65to+150

stg

Lead Temperature (10 sec) 300

L

o

C

o

C

RECOMMENDEDOPERATINGCONDITIONS

Symb o l Parame t er Value Un i t

V

V

V

T

dt/dv Input Rise and Fall Time V

1) VINfrom30%to 70%of V

Supply Voltage 2to6 V

CC

Input Voltage 0toV

I

Output Voltage 0toV

O

Operating Temperature: -40to+85

op

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

CC

CC

CC
CC

V
V

o

C

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DC SPECIFICATIONS

74AC240

Symbol Parameter Test Condit ions Value Unit

V

CC

(V)

High Level Input Voltage 3.0 VO=0.1V or

V

IH

4.5 3.15 2.25 3.15

T

=25oC-40to85

A

Min. Typ. Ma x. Min . Max.

2.1 1.5 2.1

V

-0.1 V

CC

o

C

5.5 3.85 2.75 3.85

Low Level Input Voltage 3.0 VO=0.1 Vor

V

IL

4.5 2.25 1.35 1.35

V

-0.1 V

CC

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

3 State Output Leakage

I

OZ

Current
Quiescent Supply

I

CC

3.0

4.5 I

5.5 I

3.0 I

V

I

V

IH

V

4.5 I

5.5 I

3.0

4.5 I

5.5 I

3.0 I

V

I

V

IH

V

4.5 I

5.5 I

5.5

5.5 VI=VIHor V

IO=-50µA 2.9 2.99 2.9

(*)

or

IL

=-50µA 4.4 4.49 4.4

O

=

=-50µA 5.4 5.49 5.4

O

=-12 mA 2.56 2.46

O

=-24 mA 3.86 3.76

O

=-24 mA 4.86 4.76

O

IO=50µA0.0020.1 0.1

(*)

=

or

IL

=50µA0.0010.1 0.1

O

=50µΑ 0.001 0.1 0.1

O

=12mA 0.36 0.44

O

=24mA 0.36 0.44

O

=24mA 0.36 0.44

O

VI=VCCorGND ±0.1 ±1 µA

IL

±0.5 ±5 µA

VO=VCCorGND

5.5 VI=VCCorGND 8 80 µA

Current
Dynamic Output Current

I

OLD

(note 1, 2)

I

OHD

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 Vmax 75 mA

OLD

V

=3.85Vmin -75 mA

OHD

V

V

V

V

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