Datasheet 74AC245 Datasheet (SGS Thomson Microelectronics)

74AC245

OCTAL BUS TRANSCEIVER

WITH 3-STATE OUTPUTS (NON INVERTED)

■ HIGH SPEED: t

■ LOWPOWERDISSIPATION:

=8µA (MAX.) at TA=25oC

I

CC

■ HIGH NOISE IMMUNITY:

V

NIH=VNIL

■ 50Ω TRANSMISSIONLINE DRIVING

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

PD

=28%VCC(MIN.)

CAPABILITY

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

|=IOL=24 mA (MIN)

OH

■ BALANCEDPROPAGATIONDELAY S:

t

≅ t

PLH

PHL

■ OPERATINGVOLTAGERAN GE:

V

(OPR) = 2V to 6V

CC

■ PIN AND FUNCTION COMPATIBLE WITH

74SERIES245

■ IMPROVED LATCH-UP IMMUNITY

DESCRIPTION

The AC245 is an advanced CMOS OCTAL BUS
TRANSCEIVER (3-STATE) fabricated with
sub-micron silicon gate and double-layer metal
wiring C

2

MOS technology. It is ideal for low
power applications mantaining high speed
operation similar to equivalent Bipolar Schottky
TTL.
This IC is intended for two-way asynchronous
communication between data buses and the

B

(Plastic Package)

(Micro Package)

M

ORDERCODES:

74AC245B 74AC245M

direction of data trasmission is determined by
DIR input. The enable input G can be used to
disable the device so that the buses are
effectivelyisolated.
All inputs and outputs are equipped with
protectioncircuits against static discharge,giving
them 2KV ESD immunity and transient excess
voltage.

IT IS PROHIBITED TO APPLY A SIGNAL TO A
TERMINAL WHEN IT IS IN OUTPUT MODE
AND WHEN A BUS THERMINAL IS FLOATING
(HIGH IMPEDANCE STATE)IT IS REQUESTED
TO FIX THE INPUT LEVEL BY MEANS OF
EXTERNAL PULL DOWN OR PULL UP
RESISTOR.

PINCONNECTION AND IEC LOGICSYMBOLS

April 1997

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74AC245

INPUTAND OUTPUTEQUIVALENTCIRCUIT

TRUTH TABLE

INP UT FUNCTI ON OUT PUT

G DIR A BUS B BU S

L L OUTPUT INPUT A = B

L H INPUT OUTPUT B = A

HXZZZ

X:”H”or ”L”
Z: High impedance

PIN DESCRIPTION

PI N N o SYM B O L NAME AND FUNCT I ON

1 DIR Directional Control

2, 3, 4, 5,

6, 7, 8, 9

18, 17, 16,
15, 14, 13,

12, 11

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

A1 to A8 Data Inputs/Outputs

B1 to B8 Data Inputs/Outputs

CC

Positive Supply Voltage

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.

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

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%to70%of V

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

V
V

o

C

2/8

DC SPECIFICATIONS

74AC245

Symbol Parameter Test Condition s 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. Max. 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

3 State Output Leakage

I

OZ

Current
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

5.5 VI=VIHor V

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 µΑ 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

IL

±0.5 ±5 µA

VO=VCCor GND

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 aslowas 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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74AC245

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

Symbol Parameter Test Conditi on Value Unit

o

C

ns

ns

ns

t

Propagation Delay Time 3.3

PLH

t

PHL

t

Output Enable Time 3.3

PZL

t

PZH

t

Output Disable Time 3.3

PLZ

t

PHZ

(*) Voltagerangeis 3.3V± 0.3V
(**) Voltagerange is5V± 0.5V

V

5.0

5.0

5.0

(V)

CC

(**)

(**)

(**)

T

=25oC-40to85

A

Min. Typ. Max. Min. Max.

(*)

1.5 5.5 8.5 1.5 9

1.5 4.5 6.5 1.5 7

(*)

1.5 7 12 1.5 13

1.5 5 8.5 1.5 9

(*)

1.5 8.5 12 1.5 13

1.5 6.5 9 1.5 10

CAPACITIVECHARACTERISTICS

Symbol Parameter Test Con ditions Value Uni t

T

V

CC

(V)

Input Capacitance

C

IN

I/O Capacitance

C

i/o

Power Dissipation

C

PD

5.0

5.0

5.0 20 pF

Capacitance (note 1)

1)CPDisdefined 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 bythe following equation. I

(opr)= CPD•VCC•fIN+ICC/n(percircuit)

CC

=25oC -40 to 85oC

A

Min. Typ. Max. Mi n . Max.

5

10

pF
pF

TEST CIRCUIT

TEST SWITCH

t

PLH,tPHL

t

PZL,tPLZ

t

PZH,tPHZ

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

= 500Ω or equivalent

L=R1

R

of pulse generator (typically 50Ω)

T=ZOUT

Open

2V

CC

Open

4/8

WAVEFORM 1: PROPAGATIONDELAYS (f=1MHz;50% duty cycle)

74AC245

WAVEFORM 2: OUTPUTENABLE AND DISABLE TIME(f=1MHz;50%duty cycle)

5/8

74AC245

Plastic DIP20 (0.25) MECHANICAL DATA

DIM.

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

a1 0.254 0.010

B 1.39 1.65 0.055 0.065
b 0.45 0.018

b1 0.25 0.010

D 25.4 1.000

E 8.5 0.335
e 2.54 0.100

e3 22.86 0.900

F 7.1 0.280

I 3.93 0.155
L 3.3 0.130
Z 1.34 0.053

mm inch

6/8

P001J

SO20 MECHANICAL DATA

74AC245

DIM.

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

A 2.65 0.104

a1 0.10 0.20 0.004 0.007
a2 2.45 0.096

b 0.35 0.49 0.013 0.019

b1 0.23 0.32 0.009 0.012

C 0.50 0.020

c1 45° (typ.)

D 12.60 13.00 0.496 0.512

E 10.00 10.65 0.393 0.419
e 1.27 0.050

e3 11.43 0.450

F 7.40 7.60 0.291 0.299
L 0.50 1.27 0.19 0.050

M 0.75 0.029

S8°(max.)

mm inch

P013L

7/8

74AC245

Information furnished is believed to be accurate and reliable. However,SGS-THOMSON Microelectronicsassumesno responsability for the
consequencesof use ofsuch information nor for anyinfringement of patentsor other rights ofthird parties whichmay results from its use. No
licenseisgrantedby implicationor otherwise underany patentor patent rights ofSGS-THOMSONMicroelectronics.Specificationsmentioned
in this publicationare subjectto change without notice.This publication supersedes andreplaces all informationpreviously supplied.
SGS-THOMSONMicroelectronicsproductsarenotauthorized foruseas criticalcomponents in lifesupportdevicesor systemswithoutexpress
writtenapproval of SGS-THOMSONMicroelectonics.

 1997 SGS-THOMSONMicroelectronics- Printedin Italy- AllRights Reserved

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