TECHNICAL DATA
IN74HC245A
Octal 3-State Noninverting
Bus Transceiver
High-Performance Silicon-Gate CMOS
The IN74HC245A is identical in pinout to the LS/ALS245. The
device inputs are compatible with standard CMOS outputs; with pullup
resistors, they are compatible with LS/ALSTTL outputs.
The IN74HC245A is a 3-state noninverting transceiver that is used for
2-way asynchronous communication between data buses. The device has
an active-low Output Enable pin, which is used to place the I/O ports into
high-impedance states. The Direction control determines whether data
flows from A to B or from B to A.
•
Outputs Directly Interface to CMOS, NMOS, and TTL
•
Operating Voltage Range: 2.0 to 6.0 V
•
Low Input Current: 1.0
µA
•
High Noise Immunity Characteristic of CMOS Devices
ORDERING INFORMATION
IN74HC245AN Plastic
IN74HC245ADW SOIC
T
A
= -55° to 125° C for all packages
PIN ASSIGNMENT
LOGIC DIAGRAM
FUNCTION TABLE
PIN 20=V
CC
PIN 10 = GND
Control Inputs
Output
Enable
L
Direction
L
Operation
Data Transmitted
from Bus B to
Bus A
Data Transmitted
from Bus A to
Bus B
Buses Isolated
(High Impedance
State)
L
H
H
X
X = don’t care
Rev. 00
IN74HC245A
MAXIMUM RATINGS
*
Symbol
V
CC
V
IN
V
OUT
I
IN
I
OUT
I
CC
P
D
Tstg
T
L
*
Parameter
DC Supply Voltage (Referenced to GND)
DC Input Voltage (Referenced to GND)
DC Output Voltage (Referenced to GND)
DC Input Current, per Pin
DC Output Current, per Pin
DC Supply Current, V
CC
and GND Pins
Power Dissipation in Still Air, Plastic DIP+
SOIC Package+
Storage Temperature
Lead Temperature, 1 mm from Case for 10 Seconds
(Plastic DIP or SOIC Package)
Value
-0.5 to +7.0
-1.5 to V
CC
+1.5
-0.5 to V
CC
+0.5
±20
±35
±75
750
500
-65 to +150
260
Unit
V
V
V
mA
mA
mA
mW
°C
°C
Maximum Ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the Recommended Operating Conditions.
+Derating - Plastic DIP: - 10 mW/°C from 65° to 125°C
SOIC Package: : - 7 mW/°C from 65° to 125°C
RECOMMENDED OPERATING CONDITIONS
Symbol
V
CC
V
IN
, V
OUT
T
A
t
r
, t
f
Parameter
DC Supply Voltage (Referenced to GND)
DC Input Voltage, Output Voltage (Referenced to GND)
Operating Temperature, All Package Types
Input Rise and Fall Time
(Figure 1)
V
CC
=2.0 V
V
CC
=4.5 V
V
CC
=6.0 V
Min
2.0
0
-55
0
0
0
Max
6.0
V
CC
+125
1000
500
400
Unit
V
V
°C
ns
This device contains protection circuitry to guard against damage due to high static voltages or electric fields.
However, precautions must be taken to avoid applications of any voltage higher than maximum rated voltages to this
high-impedance circuit. For proper operation, V
IN
and V
OUT
should be constrained to the range GND≤(V
IN
or
V
OUT
)≤V
CC
.
Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or V
CC
). Unused
outputs must be left open.
Rev. 00
IN74HC245A
DC ELECTRICAL CHARACTERISTICS
(Voltages Referenced to GND)
V
CC
Symbol
Parameter
Test Conditions
V
Guaranteed Limit
25
°C
to
-55°C
1.5
3.15
4.2
0.5
1.35
1.8
1.9
4.4
5.9
3.98
5.48
0.1
0.1
0.1
0.26
0.26
±0.1
±0.5
≤85
°C
1.5
3.15
4.2
0.5
1.35
1.8
1.9
4.4
5.9
3.84
5.34
0.1
0.1
0.1
0.33
0.33
±1.0
±5.0
≤125
°C
1.5
3.15
4.2
0.5
1.35
1.8
1.9
4.4
5.9
3.7
5.2
0.1
0.1
0.1
0.4
0.4
±1.0
±10
µA
µA
V
Unit
V
IH
Minimum High-
Level Input Voltage
Maximum Low -
Level Input Voltage
Minimum High-
Level Output Voltage
V
OUT
=0.1 V or V
CC
-0.1 V
⎢I
OUT
⎢≤
20
µA
V
OUT
=0.1 V or V
CC
-0.1 V
⎢I
OUT
⎢ ≤
20
µA
V
IN
=V
IH
or V
IL
⎢I
OUT
⎢ ≤
20
µA
V
IN
=V
IH
or V
IL
⎢I
OUT
⎢ ≤
6.0 mA
⎢I
OUT
⎢ ≤
7.8 mA
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
4.5
6.0
2.0
4.5
6.0
4.5
6.0
6.0
6.0
V
V
IL
V
V
OH
V
V
OL
Maximum Low-
Level Output Voltage
V
IN
= V
IL
or V
IH
⎢I
OUT
⎢ ≤
20
µA
V
IN
= V
IL
or V
IH
⎢I
OUT
⎢ ≤
6.0 mA
⎢I
OUT
⎢ ≤
7.8 mA
I
IN
I
OZ
Maximum Input
Leakage Current
Maximum Three-
State Leakage
Current
Maximum Quiescent
Supply Current
(per Package)
V
IN
=V
CC
or GND, Pin 1 or
19
Output in High-Impedance
State
V
IN
= V
IL
or V
IH
V
OUT
=V
CC
or GND, I/O Pins
V
IN
=V
CC
or GND
I
OUT
=0µA
I
CC
6.0
4.0
40
160
µA
Rev. 00
IN74HC245A
AC ELECTRICAL CHARACTERISTICS
(C
L
=50pF,Input t
r
=t
f
=6.0 ns)
V
CC
Symbol
Parameter
V
Guaranteed Limit
25
°C
to
-55°C
75
15
13
110
22
19
110
22
19
60
12
10
10
15
≤85°C
≤125°C
Unit
t
PLH
, t
PHL
Maximum Propagation Delay, A to B or B
to A (Figures 1 and 3)
Maximum Propagation Delay , Direction or
Output Enable to A or B (Figures 2 and 4)
Maximum Propagation Delay , Direction or
Output Enable to A or B (Figures 2 and 4)
Maximum Output Transition Time, Any Output
(Figures 1 and 3)
Maximum Input Capacitance (Pin 1 or Pin 19)
Maximum Three-State I/O Capacitance
(I/O in High-Impedance State)
Power Dissipation Capacitance (Per Transceiver
Channel)
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
-
-
95
19
16
140
28
24
140
28
24
75
15
13
10
15
110
22
19
165
33
28
165
33
28
90
18
15
10
15
ns
t
PLZ
, t
PHZ
ns
t
PZL
, t
PZH
ns
t
TLH
, t
THL
ns
C
IN
C
OUT
pF
pF
Typical @25°C,V
CC
=5.0 V
40
pF
C
PD
Used to determine the no-load dynamic power
consumption:
P
D
=C
PD
V
CC2
f+I
CC
V
CC
Figure 1. Switching Waveforms
Figure 2. Switching Waveforms
Rev. 00
IN74HC245A
Figure 3. Test Circuit
Figure 4. Test Circuit
EXPANDED LOGIC DIAGRAM
Rev. 00
嵌入式系统
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