当前位置：文档库 › 74ACT240B中文资料

74ACT240B中文资料

74ACT240

OCTAL BUS BUFFER

WITH 3STATE OUTPUTS (INVERTED)

April 1997s HIGH SPEED:t PD =5ns (TYP.)at V CC =5V s

LOW POWER DISSIPATION:I CC =8μA (MAX.)at T A =25o C

COMPATIBLE WITH TTL OUTPUTS V IH =2V (MIN),V IL =0.8V (MAX)

50?TRANSMISSION LINE DRIVING CAPABILITY

SYMMETRICAL OUTPUT IMPEDANCE:|I OH |=I OL =24mA (MIN)

BALANCED PROPAGATION DELAYS:t PLH ?t PHL

OPERATING VOLTAGE RANGE:V CC (OPR)=4.5V to 5.5V

PIN AND FUNCTION COMPATIBLE WITH 74SERIES 240

IMPROVED LATCH-UP IMMUNITY

DESCRIPTION

The ACT240is an advanced CMOS OCTAL BUS BUFFER (3-STATE)fabricated with sub-micron silicon gate and double-layer metal wiring C 2MOS technology.It is ideal for low power applications mantaining high speed operation similar to equivalent Bipolar Schottky TTL.

G control output governs four BUS BUFFERs.This device is desibned to be used with 3state memory address drivers,etc.

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

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

PIN CONNECTION AND IEC LOGIC SYMBOLS

ORDER CODES :

74ACT240B 74ACT240M M

(Micro Package)

B (Plastic Package)1/8

INPUT AND OUTPUT EQUIVALENT CIRCUIT

TRUTH TABLE

INPUT

OUTPUT

G An Yn L L H L H L H

X:”H”or ”L”

Z:High imp edance

PIN DESCRIPTION

PIN No

SYMBOL

NAME AND FUNCTION 11G Output Enable Input 2,4,6,81A1to 1A4Data Inputs 9,7,5,32Y1to 2Y4Data Outputs 11,13,15,172A1to 2A4Data Inputs 18,16,14,12

1Y1to 1Y4

Data Outputs 192G Output Enabel Input 10GND Ground (0V)

V CC

Positive Supply Voltage

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter

Value Unit V CC Supply Voltage -0.5to +7V V I DC Input Voltage -0.5to V CC +0.5V V O DC Output Voltage -0.5to V CC +0.5

V I IK DC Input Diode Current ±20mA I OK DC Output Diode Current ±20mA I O DC Output Current ±50mA I CC or I GND

DC V CC or Ground Current ±400mA

T stg Storage Temperature -65to +150

o C T L

Lead Temperature (10sec)

300

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

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter

Value Unit V CC Supply Voltage 4.5to 5.5V V I Input Voltage 0to V CC V V O Output Voltage

0to V CC V

T op Operating Temperature:

-40to +85

dt/dv

Input Rise and Fall Time V CC =4.5to 5.5V (note 1)

ns/V

1)V IN from 0.8V to 2.0V

74ACT240

2/8

DC SPECIFICATIONS

Symbol Parameter Test Conditions Value Unit

V CC (V)

T A=25o C-40to85o C Min.Typ.Max.Min.Max.

V IH High Level Input Voltage 4.5V O=0.1V or

V CC-0.1V 2.0 1.5 2.0

5.5 2.0 1.5 2.0

V IL Low Level Input Voltage 4.5V O=0.1V or

V CC-0.1V 1.50.80.8

5.5 1.50.80.8

V OH High Level Output

Voltage 4.5

V I(*)=

V IH or

V IL

I O=-50μA 4.4 4.49 4.4

V 5.5I O=-50μA 5.4 5.49 5.4

4.5I O=-24mA 3.86 3.76

5.5I O=-24mA 4.86 4.76

V OL Low Level Output

Voltage 4.5

V I(*)=

V IH or

V IL

I O=50μA0.0010.10.1

V 5.5I O=50mA0.0010.10.1

4.5I O=24mA0.360.44

5.5I O=24mA0.360.44

I I Input Leakage Current 5.5V I=V CC or GND±0.1±1μA

I OZ3State Output Leakage

Current 5.5V I=V IH or V IL

V O=V CC or GND

±0.5±5μA

I CCT Max I CC/Input 5.5V I=V CC-2.1V0.6 1.5mA I CC Quiescent Supply

Current

5.5V I=V CC or GND880μA

I OLD Dynamic Output Current

(note1,2)5.5V OLD=1.65V max75mA

I OHD V OH D=3.85V min-75mA

1)Maximum test duration2ms,one output loaded at time

2)Incident wave switch ing is guaranteed on transmission lines with impe dances as low as50?.

(*)All outputs loaded.

74ACT240

3/8

CAPACITIVE CHARACTERISTICS

Symbol

Parameter

Test Conditions

Value

Unit

V CC (V)

T A =25o

C -40to 85o

C Min.

Typ.Max.

Min.

Max.

C IN Input Capacitance 5.04pF C OU T Output Capacitance 5.08pF C PD

Power Dissipation Capacitance (note 1)

5.0

1)C PD isdefined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load.(Refer to Test Circuit).Ave rage operating current can be obtained by the following equation.I CC (opr)=C PD ?V CC ?f IN +I CC /n (per circuit)

AC ELECTRICAL CHARACTERISTICS (C L =50pF,R L =500?,Input t r =t f =3ns)

Symbol

Parameter

Test Condition

Value

Unit

V CC (V)

T A =25o

C -40to 85o C Min.Typ.Max.Min.Max.

t PLH t PHL Propagation Delay Time 5.0(*)

1.5 5.07.5 1.58.5ns t PZL t PZH Output Enable Time 5.0(*)

1.5 6.08.5 1.59.5ns t PLZ t PHZ

Output Disable Time

5.0

(*)

1.5

6.5

10.0

1.5

10.5

(*)Voltage range is 5V ±0.5V

TEST CIRCUIT

TEST

SWITCH t PLH ,t PHL Open t PZL ,t PLZ 2V CC t PZH ,t PHZ

Open

C L =50pF or equivalent (includes jig and probe capacitance )R L =R 1=500?or equiva lent

R T =Z OUT of pulse generator (typically 50?)

74ACT240

4/8

74ACT240 WAVEFORM1:PROPAGATION DELAYS(f=1MHz;50%duty cycle)

WAVEFORM2:OUTPUT ENABLE AND DISABLE TIME(f=1MHz;50%duty cycle)

5/8

DIM.

inch MIN.

TYP.

MAX.

MIN.TYP.

MAX.

a10.2540.010B 1.39

1.65

0.055

0.065

b 0.450.018b10.25

0.010

D 25.4

1.000E 8.50.335e

2.540.100e322.86

0.900

F 7.10.280I 3.93

0.155

L 3.3

0.130

1.34

0.053

P001J

Plastic DIP20(0.25)MECHANICAL DATA

74ACT240

6/8

74ACT240

SO20MECHANICAL DATA

mm inch

DIM.

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

A 2.650.104

a10.100.200.0040.007

a2 2.450.096

b0.350.490.0130.019

b10.230.320.0090.012

C0.500.020

c145°(typ.)

D12.6013.000.4960.512

E10.0010.650.3930.419

e 1.270.050

e311.430.450

F7.407.600.2910.299

L0.50 1.270.190.050

M0.750.029

S8°(max.)

P013L

7/8

74ACT240

Information furnished is believed to be accurate and reliable.However,SGS-THOMSON Microelectronics assumes no responsabilit y for the consequences of use of such information nor for any infringemen t of patents or other rights of third parties which may results from its use.No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectr onics.Specifications mention ed in this publication are subject to change without notice.This publication supersede s and replaces all information previously supplied.

SGS-THOMSON Microelectr onics products are not auth orized for use as critical compon ents in life support devices or systems without expre ss written approval of SGS-THOMSON Microelectonics.

?1997SGS-THOMSON Microelectronics-Printed in Italy-All Rights Reserve d

SGS-THOMSON Microelectronics GROUP OF COMPANIES

Australia-Brazil-Canada-China-France-Germany-Hong Kong-Italy-Japan-Korea-Malaysia-Malta-Morocco-The Netherlands-Singapore-Spain-Sweden-Switzerland-Taiwan-Thailand-United Kingdom-U.S.A

8/8