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Электронный компонент: T54LS279

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TL F 6420
54LS279DM54LS279DM74LS279
Quad
S
-R
Latches
May 1989
54LS279 DM54LS279 DM74LS279
Quad S-R Latches
General Description
The 'LS279 consists of four individual and independent Set-
Reset Latches with active low inputs Two of the four latch-
es have an additonal S input ANDed with the primary S
input A low on any S input while the R input is high will be
stored in the latch and appear on the corresponding Q out-
put as a high A low on the R input while the S input is high
will clear the Q output to a low Simultaneous transistion of
the R and S inputs from low to high will cause the Q output
to be indeterminate Both inputs are voltage level triggered
and are not affected by transition time of the input data
Features
Y
Alternate military aerospace device (54LS279) is avail-
able Contact a National Semiconductor Sales Office
Distributor for specifications
Connection Diagram
Dual-In-Line Package
TL F 6420 1
Order Number 54LS279DMQB 54LS279FMQB 54LS279LMQB
DM54LS279J DM74LS279M or DM74LS279N
See NS Package Number E20A J16A M16A N16E or W16A
Function Table
Inputs
Output
S(1)
R
Q
L
L
H
L
H
H
H
L
L
H
H
Q
0
H
e
High Level
L
e
Low Level
Q
0
e
The Level of Q before the indicated input conditions were established
This output level is pseudo stable that is it may not persist when the S and R
inputs return to their inactive (high) level
Note 1
For latches with double S inputs
H
e
both S inputs high
L
e
one or both S inputs low
C1995 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
DM54LS and 54LS
b
55 C to
a
125 C
DM74LS
0 C to
a
70 C
Storage Temperature Range
b
65 C to
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
DM54LS279
DM74LS279
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
0 4
b
0 4
mA
I
OL
Low Level Output Current
4
8
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
e b
18 mA
b
1 5
V
V
OH
High Level Output
V
CC
e
Min I
OH
e
Max
DM54
2 5
3 5
V
Voltage
V
IL
e
Max V
IH
e
Min
DM74
2 7
3 5
V
OL
Low Level Output
V
CC
e
Min I
OL
e
Max
DM54
0 25
0 4
Voltage
V
IL
e
Max V
IH
e
Min
DM74
0 35
0 5
V
I
OL
e
4 mA V
CC
e
Min
DM74
0 25
0 4
I
I
Input Current
Max
V
CC
e
Max V
I
e
7V
0 1
mA
Input Voltage
I
IH
High Level Input
V
CC
e
Max V
I
e
2 7V
20
m
A
Current
I
IL
Low Level Input
V
CC
e
Max V
I
e
0 4V
b
0 4
mA
Current
I
OS
Short Circuit
V
CC
e
Max
DM54
b
20
b
100
mA
Output Current
(Note 2)
DM74
b
20
b
100
I
CC
Supply Current
V
CC
e
Max (Note 3)
3 8
7
mA
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
Note 3
I
CC
is measured with all R inputs grounded all S inputs at 4 5V and all outputs open
2
Switching Characteristics
at V
CC
e
5V and T
A
e
25 C (See Section 1 for Test Waveforms and Output Load)
From (Input)
R
L
e
2 kX
Symbol
Parameter
To (Output)
C
L
e
15 pF
C
L
e
50 pF
Units
Min
Max
Min
Max
t
PLH
Propagation Delay Time
S to
22
25
ns
Low to High Level Output
Q
t
PHL
Propagation Delay Time
S to
15
23
ns
High to Low Level Output
Q
t
PHL
Propagation Delay Time
R to
27
33
ns
High to Low Level Output
Q
3
Physical Dimensions
inches (millimeters)
Ceramic Leadless Chip Carrier Package (E)
Order Number 54LS279LMQB
NS Package Number E20A
16-Lead Ceramic Dual-In-Line Package (J)
Order Number 54LS279DMQB or DM54LS279J
NS Package Number J16A
4
Physical Dimensions
inches (millimeters) (Continued)
16-Lead Small Outline Molded Package (M)
Order Number DM74LS279M
NS Package Number M16A
16-Lead Molded Dual-In-Line Package (N)
Order Number DM74LS279N
NS Package Number N16E
5
54LS279DM54LS279DM74LS279
Quad
S
-R
Latches
Physical Dimensions
inches (millimeters) (Continued)
16-Lead Ceramic Flat Package (W)
Order Number 54LS279FMQB or DM54LS279W
NS Package Number W16A
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failure to perform when properly used in accordance
support device or system or to affect its safety or
with instructions for use provided in the labeling can
effectiveness
be reasonably expected to result in a significant injury
to the user
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