Data Sheet

NTE74LS279
Integrated Circuit
TTL − Quad Set−Reset Latch
Description:
The NTE74LS279 offers 4 basic S−R flip−flop latches in a 16−Lead plastic DIP type package. Under conventional operation, the S−R inputs are normally held high. When the S input is pulsed low, the Q output
will be set high. When R is pulsed low, the Q output will be reset low. Normally, the S−R inputs should
not be taken low simultaneously. The Q output will be unpredictable in this condition.
Absolute Maximum Ratings: (Note 1)
Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Input Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Operating Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0C to +70C
Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65C to +150C
Note 1. Unless otherwise specified, all voltages are referenced to GND.
Recommended Operating Conditions:
Parameter
Symbol
Min
Typ
Max
Unit
Supply Voltage
VCC
4.75
5.0
5.25
V
High−Level Output Voltage
VOH
2
−
−
V
Low−Level Output Voltage
VOL
−
−
0.8
V
High−Level Output Current
IOH
−
−
−0.4
mA
Low−Level Output Current
IOL
−
−
8
mA
Pulse Duration, Low
tw
20
−
−
ns
Operating Temperature Range
TA
0
−
+70
C
Electrical Characteristics: (Note 2, Note 3)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
−
−
−1.5
V
2.7
3.4
−
V
IOL = 4mA
−
0.25
0.4
V
IOL = 8mA
−
0.25
0.5
V
Input Clamp Voltage
VIK
VCC = MIN, II = −18mA
High Level Output Voltage
VOH
VCC = MIN, VIL = MAX, IOH = −0.4mA
Low Level Output Voltage
VOL
VCC = MIN, VIH = 2V
Input Current
II
VCC = MAX, VI = 7V
−
−
0.1
mA
High Level Input Current
IIH
VCC = MAX, VI = 2.7V
−
−
20
A
Low Level Input Current
IIL
VCC = MAX, VI = 0.4V
−
−
−0.2
mA
Short−Circuit Output Current
IOS
VCC = MAX, Note 4
−20
−
−100
mA
Supply Current
ICC
VCC = MAX, Note 5
−
3.8
7
mA
Note 2. .For conditions shown as MIN or MAX, use the appropriate value specified under “Recommended
Operation Conditions”.
Note 3. All typical values are at VCC = 5V, TA = +25C.
Note 4. Not more than one output should be shorted at a time, and the duration of the short−circuit
should not exceed one second.
Note 5. ICC is measured with all R inputs grounded, all S inputs at 4.5V and all outputs open.
Switching Characteristics: (VCC = 5V, RL = 667, TA = +25C unless otherwise specified)
Parameter
Propagation Delay Time
(From S Input to Q Output)
Propagation Delay Time
(From R Input to Q Output)
Symbol
tPLH
Test Conditions
Min
Typ
Max
Unit
−
12
22
ns
tPHL
−
13
21
ns
tPHL
−
15
27
ns
RL = 2k, CL = 15pF
Function Table:
Output
Inputs
S{
R
Q
H
H
Q0
L
H
H
H
L
L
L
L
H*
H = HIGH Level
L = LOW Level
Q0 = The level of Q before the indicated
input conditions were established.
* This configuration is nonstable; that is,
it may not persist when the S and R inputs
return to their inactive (high) level.
{ For latches with double S inputs:
H = Both S inputs high
L = One or both S inputs low
Logic Diagram
(Latches 2 and 4)
(Latches 1 and 3)
R
R
S1
S2
Q
Q
S
Pin Connection Diagram
1R 1
16 VCC
1S1 2
1S2 3
15 4S
14 4R
1Q 4
13 4Q
2R 5
12 3S2
1S 6
11 3S1
10 3R
2Q 7
GND 8
9 3Q
16
9
1
8
.870 (22.0) Max
.260 (6.6)
Max
.200
(5.08)
Max
.100 (2.54)
.700 (17.78)
.099 (2.5) Min