DM74LS244WM
TL/F/8442
54LS244/DM74LS244 Octal TRI-STATE Buffers/Line Drivers/Line Receivers
August 1989
54LS244/DM74LS244 Octal TRI-STATE
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Buffers/Line Drivers/Line Receivers
General Description
These buffers/line drivers are designed to improve both the
performance and PC board density of TRI-STATE buffers/
drivers employed as memory-address drivers, clock drivers,
and bus-oriented transmitters/receivers. Featuring 400 mV
of hysteresis at each low current PNP data line input, they
provide improved noise rejection and high fanout outputs
and can be used to drive terminated lines down to 133X.
Features
Y
TRI-STATE outputs drive bus lines directly
Y
PNP inputs reduce DC loading on bus lines
Y
Hysteresis at data inputs improves noise margins
Y
Typical I
OL
(sink current)
54LS 12 mA
74LS 24 mA
Y
Typical I
OH
(source current)
54LS
b
12 mA
74LS
b
15 mA
Y
Typical propagation delay times
Inverting 10.5 ns
Noninverting 12 ns
Y
Typical enable/disable time 18 ns
Y
Typical power dissipation (enabled)
Inverting 130 mW
Noninverting 135 mW
Connection Diagram
Dual-In-Line Package
TL/F/8442– 1
Order Number 54LS244DMQB, 54LS244FMQB, 54LS244LMQB,
DM74LS244WM or DM74LS244N
See NS Package Number E20A, J20A, M20B, N20A or W20A
Function Table
Inputs Output
G AY
LL L
LH H
HX Z
L
e
Low Logic Level
H
e
High Logic Level
X
e
Either Low or High Logic Level
Z
e
High Impedance
TRI-STATE
É
is a registered trademark of National Semiconductor Corporation.
C
1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.
Absolute Maximum Ratings (Note)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage 7V
Input Voltage 7V
Operating Free Air Temperature Range
54LS
b
55
§
Cto
a
125
§
C
DM74LS 0
§
Cto
a
70
§
C
Storage Temperature Range
b
65
§
Cto
a
150
§
C
Note:
The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaran-
teed. The device should not be operated at these limits. The
parametric values defined in the ‘‘Electrical Characteristics’’
table 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 Parameter
54LS244 DM74LS244
Units
Min Nom Max Min Nom Max
V
CC
Supply Voltage 4.5 5 5.5 4.75 5 5.25 V
V
IH
High Level Input Voltage 2 2 V
V
IL
Low Level Input Voltage 0.7 0.8 V
I
OH
High Level Output Current
b
12
b
15 mA
I
OL
Low Level Output Current 12 24 mA
T
A
Free Air Operating Temperature
b
55 125 0 70
§
C
Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)
Symbol Parameter Conditions Min
Typ
Max Units
(Note 1)
V
I
Input Clamp Voltage V
CC
e
Min, I
I
eb
18 mA
b
1.5 V
HYS Hysteresis (V
T
a
b
V
T
b
)V
CC
e
Min
0.2 0.4 V
Data Inputs Only
V
OH
High Level Output Voltage V
CC
e
Min, V
IH
e
Min DM74
2.7
V
IL
e
Max, I
OH
eb
1mA
V
CC
e
Min, V
IH
e
Min 54LS/DM74
2.4 3.4 V
V
IL
e
Max, I
OH
eb
3mA
V
CC
e
Min, V
IH
e
Min 54LS/DM74
2
V
IL
e
0.5V, I
OH
e
Max
V
OL
Low Level Output Voltage V
CC
e
Min I
OL
e
12 mA 54LS/DM74 0.4
V
IL
e
Max V
I
OL
e
Max DM74 0.5
V
IH
e
Min
I
OZH
Off-State Output Current, V
CC
e
Max V
O
e
2.7V
20 mA
High Level Voltage Applied V
IL
e
Max
I
OZL
Off-State Output Current,
V
IH
e
Min
V
O
e
0.4V
b
20 mA
Low Level Voltage Applied
I
I
Input Current at Maximum V
CC
e
Max V
I
e
7V (DM74)
0.1 mA
Input Voltage V
I
e
10V (54LS)
I
IH
High Level Input Current V
CC
e
Max V
I
e
2.7V 20 mA
I
IL
Low Level Input Current V
CC
e
Max V
I
e
0.4V
b
0.5
b
200 mA
I
OS
Short Circuit Output Current V
CC
e
Max (Note 2)
54LS
b
50
b
225 mA
DM74
b
40
I
CC
Supply Current V
CC
e
Max, Outputs High 13 23
Outputs Open
Outputs Low 27 46 mA
Outputs Disabled 32 54
Note 1: All typicals are at V
CC
e
5V, T
A
e
25
§
C.
Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.
2
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