DM74LS245 3-STATE Octal Bus Transceiver
August 1986
Revised March 2000
DM74LS245
3-STATE Octal Bus Transceiver
General Description
These octal bus transceivers are designed for asynchro-
nous two-way communication between data buses. The
control function implementation minimizes external timing
requirements.
The device allows data transmission from the A Bus to the
B Bus or from the B Bus to the A Bus depending upon the
logic level at the direction control (DIR) input. The enable
input (G) can be used to disable the device so that the
buses are effectively isolated.
Features
s
Bi-Directional bus transceiver in a high-density 20-pin
package
s
3-STATE outputs drive bus lines directly
s
PNP inputs reduce DC loading on bus lines
s
Hysteresis at bus inputs improve noise margins
s
Typical propagation delay times, port-to-port 8 ns
s
Typical enable/disable times 17 ns
s
I
OL
(sink current)
24 mA
s
I
OH
(source current)
−15
mA
Ordering Code:
Order Number
DM74LS245WM
DM74LS245SJ
DM74LS245N
Package Number
M20B
M20D
N20A
Package Description
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Function Table
Enable
G
L
L
H
H
=
HIGH Level
L
=
LOW Level
X
=
Irrelevant
Direction
Control
DIR
L
H
X
Operation
B Data to A Bus
A Data to B Bus
Isolation
© 2000 Fairchild Semiconductor Corporation
DS006413
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DM74LS245
Absolute Maximum Ratings
(Note 1)
Supply Voltage
Input Voltage
DIR or G
A or B
Operating Free Air Temperature Range
Storage Temperature Range
7V
5.5V
0°C to
+70°C
−65°C
to
+150°C
7V
Note 1:
The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Free Air Operating Temperature
0
Parameter
Min
4.75
2
0.8
−15
24
70
Nom
5
Max
5.25
Units
V
V
V
mA
mA
°C
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
V
I
HYS
V
OH
Parameter
Input Clamp Voltage
Hysteresis (V
T+
−
V
T−
)
HIGH Level
Output Voltage
Conditions
V
CC
=
Min, I
I
= −18
mA
V
CC
=
Min
V
CC
=
Min, V
IH
=
Min
V
IL
=
Max, I
OH
= −1
mA
V
CC
=
Min, V
IL
=
Min
V
IL
=
Max, I
OH
= −3
mA
V
CC
=
Min, V
IH
=
Min
V
IL
=
0.5V, I
OH
=
Max
V
OL
LOW Level
Output Voltage
I
OZH
I
OZL
I
I
I
IH
I
IL
I
OS
I
CC
Off-State Output Current,
HIGH Level Voltage Applied
Off-State Output Current,
LOW Level Voltage Applied
Input Current at Maximum
Input Voltage
HIGH Level Input Current
LOW Level Input Current
Short Circuit Output Current
Supply Current
V
CC
=
Max, V
I
=
2.7V
V
CC
=
Max, V
I
=
0.4V
V
CC
=
Max (Note 3)
Outputs HIGH
Outputs LOW
Outputs at Hi-Z
Note 2:
All typicals are at V
CC
=
5V, T
A
=
25°C.
Note 3:
Not more than one output should be shorted at a time, not to exceed one second duration
Min
Typ
(Note 2)
0.4
Max
−1.5
Units
V
V
0.2
2.7
2.4
2
I
OL
=
12 mA
I
OL
=
Max
V
O
=
2.7V
V
O
=
0.4V
A or B
DIR or G
V
I
=
5.5V
V
I
=
7V
3.4
V
V
CC
=
Min
V
IL
=
Max
V
IH
=
Min
V
CC
=
Max
V
IL
=
Max
V
IH
=
Min
V
CC
=
Max
0.4
0.5
20
−200
0.1
0.1
20
−0.2
−40
48
V
CC
=
Max
62
64
−225
70
90
95
mA
V
µA
µA
mA
µA
mA
mA
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2
DM74LS245
Switching Characteristics
V
CC
=
5V, T
A
=
25°C
Symbol
t
PLH
t
PHL
t
PZL
t
PZH
t
PLZ
t
PHZ
t
PLH
t
PHL
t
PZL
t
PZH
Parameter
Propagation Delay Time,
LOW-to-HIGH Level Output
Propagation Delay Time,
HIGH-to-LOW Level Output
Output Enable Time
to LOW Level
Output Enable Time
to HIGH Level
Output Disable Time
from LOW Level
Output Disable Time
from HIGH Level
Propagation Delay Time,
LOW-to-HIGH Level Output
Propagation Delay Time,
HIGH-to-LOW Level Output
Output Enable Time
to LOW Level
Output Enable Time
to HIGH Level
C
L
=
150 pF
R
L
=
667Ω
C
L
=
5 pF
R
L
=
667Ω
Conditions
C
L
=
45 pF
R
L
=
667Ω
Min
Max
12
12
40
40
25
25
16
17
45
45
Units
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
3
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DM74LS245
Physical Dimensions
inches (millimeters) unless otherwise noted
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
Package Number M20B
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4
DM74LS245
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
Package Number M20D
5
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