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National Semiconductor |
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
www.DataSheet.net/
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
LL
LH
HL
HH
H
H
L
Q0
H e High Level
L e Low Level
Q0 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 TL F 6420
RRD-B30M105 Printed in U S A
Datasheet pdf - http://www.DataSheet4U.co.kr/
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
b55 C to a125 C
DM74LS
0 C to a70 C
Storage Temperature Range
b65 C to a150 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
VCC
VIH
VIL
IOH
IOL
TA
Parameter
Supply Voltage
High Level Input Voltage
Low Level Input Voltage
High Level Output Current
Low Level Output Current
Free Air Operating Temperature
Min
45
2
b55
DM54LS279
Nom
Max
5 55
07
b0 4
4
125
Min
4 75
2
0
DM74LS279
Nom
Max
5 5 25
08
b0 4
8
70
Units
V
V
V
mA
mA
C
Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
VI
VOH
VOL
Input Clamp Voltage
High Level Output
Voltage
Low Level Output
Voltage
VCC e Min II e b18 mA
VCC e Min IOH e Max
VIL e Max VIH e Min
VCC e Min IOL e Max
VIL e Max VIH e Min
DM54
25
DM74
27
DM54
DM74
www.DataSheet.net/
IOL e 4 mA VCC e Min
DM74
II
Input Current Max
VCC e Max VI e 7V
Input Voltage
IIH
High Level Input
VCC e Max VI e 2 7V
Current
IIL
Low Level Input
VCC e Max VI e 0 4V
Current
IOS Short Circuit
Output Current
VCC e Max
(Note 2)
DM54
DM74
b20
b20
ICC Supply Current
VCC e Max (Note 3)
Note 1 All typicals are at VCC e 5V TA 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 ICC is measured with all R inputs grounded all S inputs at 4 5V and all outputs open
Typ
(Note 1)
35
35
0 25
0 35
0 25
38
Max
b1 5
04
05
04
01
20
b0 4
b100
b100
7
Units
V
V
V
mA
mA
mA
mA
mA
2
Datasheet pdf - http://www.DataSheet4U.co.kr/
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