ST M74HCT245 User Manual

M74HCT245

OCTAL BUS TRANSCEIVER

WITH 3 STATE OUTPUTS (NON INVERTED)

■ HIGH SPEED:

t

= 13ns (TYP.) at VCC = 4.5V

PD

■ LOW POWER DISSIPATION:

I

= 4µA(MAX.) at TA=25°C

CC

■ COMPA TIBLE WITH TTL OUTPUTS :

V

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

IH

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

| = IOL = 6mA (MIN)

OH

■ BALANCED PROPAGATION DELAYS:

t

≅ t

PHL

PLH

■ PIN AND FUNCTION COMPATIBLE WITH

74 SERIES 245

DESCRIPTION

The M74HCT245 is an advanced high-speed
CMOS OCTAL BUS TRANSCEIVER (3-STATE)
fabricated with silicon gate C

2

MOS technology.
This IC is intended for two-way asynchronous
communication between data buses, and the
direction of data transmission is determined by
DIR input. The enable input G

can be used to
disable the device so that the buses are effectively
isolated.

TSSOPDIP SOP

ORDER CODES

PACKAGE TUBE T & R

DIP M74HCT245B1R

SOP M74HCT245M1R M74HCT245RM13TR

TSSOP M74HCT245TTR

All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.
All floating bus terminals during High Z State must
be held HIGH or LOW.

PIN CONNECTION AND IEC LOGIC SYMBOLS

1/9August 2001

M74HCT245

INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION

PIN No SYMBOL NAME AND FUNCTION

1 DIR Directional Control

2, 3, 4, 5, 6,

7, 8, 9

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

12, 11

19 G
10 GND Ground (0V)
20 V

TRUTH TABLE

INPUTS FUNCTION OUTPUT

A1 to A8 Data Inputs/Outputs

B1 to B8 Data Inputs/Outputs

CC

Output Enable Input

Positive Supply Voltage

G

DIR A BUS B BUS Yn

L L OUTPUT INPUT A = B
L H INPUT OUTPUT B = A

HXZZZ

X : Don’t Care
Z : High Impedance

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

I

I

OK

I

I

or I

CC

P

T

T

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
(*) 500mW at 65

Supply Voltage

CC

DC Input Voltage -0.5 to VCC + 0.5

I

DC Output Voltage -0.5 to VCC + 0.5

O

DC Input Diode Current

IK

DC Output Diode Current
DC Output Current

O

DC VCC or Ground Current

GND

Power Dissipation

D

Storage Temperature

stg

Lead Temperature (10 sec)

L

; derate to 30 0m W by 10mW/°C from 65

°C

°C to 85°C

-0.5 to +7 V
V
V

± 20 mA
± 20 mA
± 35 mA
± 70 mA

500(*) mW

-65 to +150 °C

300 °C

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter Value Unit

2/9

V

V

V
T
t

r

Supply Voltage

CC

Input Voltage 0 to V

I

Output Voltage 0 to V

O

Operating Temperature

op

, t

Input Rise and Fall Time (VCC = 4.5 to 5.5V)

f

4.5 to 5.5 V

CC
CC

-55 to 125 °C
0 to 500 ns

V
V

DC SPECIFICATIONS

Symbol Parameter

V

V

V

V

I

I

∆ I

High Level Input

IH

Voltage

Low Level Input

IL

Voltage

High Level Output

OH

Voltage
Low Level Output

OL

Voltage

I

Input Leakage

I

Current
High Impedance

OZ

Output Leakage
Current

Quiescent Supply

CC

Current
Additional Worst

CC

Case Supply
Current

Test Condition Value

T

= 25°C

V

(V)

CC

A

Min. Typ. Max. Min. Max. Min. Max.

4.5
to

2.0 2.0 2.0 V

5.5

4.5
to

0.8 0.8 0.8 V

5.5

4.5

4.5

5.5

5.5

5.5

IO=-20 µA

I

=-6.0 mA

O

IO=20 µA

I

=6.0 mA

O

= VCC or GND

V

I

= VIH or V

V

I

VO = VCC or GND

= VCC or GND

V

I

5.5 Per Input pin

= 0.5V or

V

I

V

= 2.4V

I

4.4 4.5 4.4 4.4

4.18 4.31 4.13 4.10

0.0 0.1 0.1 0.1

0.17 0.26 0.33 0.40
± 0.1 ± 1 ± 1 µA

IL

± 0.5 ± 5 ± 10 µA

2.0 2.9 3.0 mA

Other Inputs at

V

or GND

CC

I

= 0

O

M74HCT245

-40 to 85°C -55 to 125°C

44080µA

Unit

V

V

AC ELECTRICAL CHARACTERISTICS (C

Test Condition Value

Symbol Parameter

t

TLH tTHL

t

PLH tPHL

t

PZL tPZH

Output Transition
Time

Propagation Delay
Time

High Impedance
Output Enable
Time

t

PLZ tPHZ

High Impedance
Output Disable
Time

C

V

CC

(V)

L

(pF)

4.5 50 7 12 15 18 ns
50 13 22 28 33

4.5

150 18 30 38 45

50

4.5

150

4.5 50

= 50 pF, Input tr = tf = 6ns)

L

= 25°C

T

A

Min. Typ. Max. Min. Max. Min. Max.

R

= 1 KΩ

L

R

= 1 KΩ

L

R

= 1 KΩ

L

19 30 38 45
24 38 48 57

17 30 38 45 ns

-40 to 85°C -55 to 125°C

Unit

ns

ns

3/9