1/9
August 2001
s
HIGH SPEED:
t
PD
= 13ns (TYP.) at V
CC
= 4.5V
s
LOW POWER DISSIPATION:
I
CC
= 4
A(MAX.) at T
A
=25C
s
COMPATIBLE WITH TTL OUTPUTS :
V
IH
= 2V (MIN.) V
IL
= 0.8V (MAX)
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 6mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
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.
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.
M74HCT245
OCTAL BUS TRANSCEIVER
WITH 3 STATE OUTPUTS (NON INVERTED)
PIN CONNECTION AND IEC LOGIC SYMBOLS
ORDER CODES
PACKAGE
TUBE
T & R
DIP
M74HCT245B1R
SOP
M74HCT245M1R
M74HCT245RM13TR
TSSOP
M74HCT245TTR
TSSOP
DIP
SOP
M74HCT245
2/9
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
TRUTH TABLE
X : Don't Care
Z : High Impedance
ABSOLUTE MAXIMUM RATINGS
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
C; derate to 300mW by 10mW/
C from 65
C to 85
C
RECOMMENDED OPERATING CONDITIONS
PIN No
SYMBOL
NAME AND FUNCTION
1
DIR
Directional Control
2, 3, 4, 5, 6,
7, 8, 9
A1 to A8
Data Inputs/Outputs
18, 17, 16,
15, 14, 13,
12, 11
B1 to B8
Data Inputs/Outputs
19
G
Output Enable Input
10
GND
Ground (0V)
20
V
CC
Positive Supply Voltage
INPUTS
FUNCTION
OUTPUT
G
DIR
A BUS
B BUS
Yn
L
L
OUTPUT
INPUT
A = B
L
H
INPUT
OUTPUT
B = A
H
X
Z
Z
Z
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
-0.5 to +7
V
V
I
DC Input Voltage
-0.5 to V
CC
+ 0.5
V
V
O
DC Output Voltage
-0.5 to V
CC
+ 0.5
V
I
IK
DC Input Diode Current
20
mA
I
OK
DC Output Diode Current
20
mA
I
O
DC Output Current
35
mA
I
CC
or I
GND
DC V
CC
or Ground Current
70
mA
P
D
Power Dissipation
500(*)
mW
T
stg
Storage Temperature
-65 to +150
C
T
L
Lead Temperature (10 sec)
300
C
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
4.5 to 5.5
V
V
I
Input Voltage
0 to V
CC
V
V
O
Output Voltage
0 to V
CC
V
T
op
Operating Temperature
-55 to 125
C
t
r
, t
f
Input Rise and Fall Time (V
CC
= 4.5 to 5.5V)
0 to 500
ns
M74HCT245
3/9
DC SPECIFICATIONS
AC ELECTRICAL CHARACTERISTICS (C
L
= 50 pF, Input t
r
= t
f
= 6ns)
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
IH
High Level Input
Voltage
4.5
to
5.5
2.0
2.0
2.0
V
V
IL
Low Level Input
Voltage
4.5
to
5.5
0.8
0.8
0.8
V
V
OH
High Level Output
Voltage
4.5
I
O
=-20
A
4.4
4.5
4.4
4.4
V
I
O
=-6.0 mA
4.18
4.31
4.13
4.10
V
OL
Low Level Output
Voltage
4.5
I
O
=20
A
0.0
0.1
0.1
0.1
V
I
O
=6.0 mA
0.17
0.26
0.33
0.40
I
I
Input Leakage
Current
5.5
V
I
= V
CC
or GND
0.1
1
1
A
I
OZ
High Impedance
Output Leakage
Current
5.5
V
I
= V
IH
or V
IL
V
O
= V
CC
or GND
0.5
5
10
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
80
A
I
CC
Additional Worst
Case Supply
Current
5.5
Per Input pin
V
I
= 0.5V or
V
I
= 2.4V
Other Inputs at
V
CC
or GND
I
O
= 0
2.0
2.9
3.0
mA
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
C
L
(pF)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
t
TLH
t
THL
Output Transition
Time
4.5
50
7
12
15
18
ns
t
PLH
t
PHL
Propagation Delay
Time
4.5
50
13
22
28
33
ns
150
18
30
38
45
t
PZL
t
PZH
High Impedance
Output Enable
Time
4.5
50
R
L
= 1 K
19
30
38
45
ns
150
R
L
= 1 K
24
38
48
57
t
PLZ
t
PHZ
High Impedance
Output Disable
Time
4.5
50
R
L
= 1 K
17
30
38
45
ns
M74HCT245
4/9
CAPACITIVE CHARACTERISTICS
1) C
PD
is defined 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 by the following equation. I
CC(opr)
= C
PD
x V
CC
x f
IN
+ I
CC
/8 (per circuit)
TEST CIRCUIT
C
L
= 50pF/150pF or equivalent (includes jig and probe capacitance)
R
1
= 1K
or equivalent
R
T
= Z
OUT
of pulse generator (typically 50
)
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
C
IN
Input Capacitance
DIR, G
5
10
10
10
pF
C
I/OUT
Output
Capacitance
An, Bn
13
pF
C
PD
Power Dissipation
Capacitance (note
1)
41
pF
TEST
SWITCH
t
PLH
, t
PHL
Open
t
PZL
, t
PLZ
V
CC
t
PZH
, t
PHZ
GND
M74HCT245
5/9
WAVEFORM 1 : PROPAGATION DELAY TIME (f=1MHz; 50% duty cycle)
WAVEFORM 2 : OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
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