NSC 54122

54122/DM74122
Retriggerable Resettable Multivibrator
General Description
The ’122 features positive and negative DC level triggering
inputs, complementary outputs, an optional 10 kX internal
timing resistor and an overriding Direct Clear (CD) input.
When the circuit is in the quasi-stable (delay) state, another
trigger applied to the inputs (per Truth Table) will cause the
delay period to start again, without disturbing the outputs.
This process can be repeated indefinitely and thus the output pulse period (Q HIGH, Q LOW) can be made as long as
desired. Alternatively, a delay period can be terminated
by a LOW signal applied to CD, which also prevents triggering. An internal connection from CD to the input gate makes
it possible to trigger the circuit by a positive-going signal on
CD, as shown in the Truth Table. For timing capacitor values
greater than 1000 pF, the output pulse width is defined as
follows:
tw e 0.32 RXCX (1.0 a 0.7/RX)
Connection Diagram
Logic Symbol
Where tw is in ns, RX is in kX and CX is in pF.
Dual-In-Line Package
TL/F/10212 – 2
VCC e Pin 14
GND e Pin 7
NC e Pins 10 and 12
TL/F/10212 – 1
Order Number 54122DMQB, 54122FMQB or DM74122N
See NS Package Number J14A, N14A or W14B
Pin Names
A1, A2
B1, B2
CD
Q, Q
C1995 National Semiconductor Corporation
TL/F/10212
Description
Trigger Inputs (Active Falling Edge)
Trigger Inputs (Active Rising Edge)
Direct Clear Inputs (Active LOW)
Outputs
RRD-B30M105/Printed in U. S. A.
54122/DM74122 Retriggerable Resettable Multivibrator
June 1989
Absolute Maximum Ratings
(Note)
Note: 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’’
table are not guaranteed at the absolute maximum ratings.
The ‘‘Recommended Operating Conditions’’ table will define
the conditions for actual device operation.
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage
7V
Input Voltage
5.5V
Operating Free Air Temperature Range
b 55§ C to a 125§ C
54
DM74
0§ C to a 70§ C
b 65§ C to a 150§ C
Storage Temperature Range
Recommended Operating Conditions
Symbol
54122
Parameter
VCC
Supply Voltage
VIH
High Level Input Voltage
VIL
Low Level Input Voltage
IOH
High Level Output Current
IOL
Low Level Output Current
TA
Free Air Operating Temperature
DM74122
Units
Min
Nom
Max
Min
Nom
Max
4.5
5
5.5
4.75
5
5.5
2
2
V
0.8
0.8
V
b 0.8
b 0.8
mA
16
mA
70
§C
16
b 55
V
125
b 55
Recommended Operating Conditions VCC e a 5.0V, TA e a 25§ C
Symbol
Parameter
DM74
Conditions
Min
tw
Trigger Pulse Width
RX
External Timing Resistor
40
XC
Over Operating VCC and
Temperature Range
XM
CX
Units
Max
External Timing Capacitor
ns
5.0
50
5.0
25
kX
No Restrictions
pF
Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
(Note 1)
Max
Units
b 1.5
V
VI
Input Clamp Voltage
VCC e Min, II e b12 mA
VOH
High Level Output Voltage
VCC e Min, IOH e Max,
VIL e Max
VOL
Low Level Output Voltage
VCC e Min, VIH e Min
0.4
V
II
Input Current
Input Voltage
VCC e Max, VI e 5.5V
1
mA
IIH
High Level Input Current
IIL
@
Max
Low Level Input Current
VCC e Max, VI e 2.4V
VCC e Max, VI e 0.4V
IOS
Short Circuit Output Current
VCC e Max (Note 2)
ICC
Supply Current
VCC e Max
2.4
Inputs
40
Clear
80
Inputs
b 1.6
Clear
b 3.2
b 10
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.
2
V
mA
mA
b 40
mA
28
mA
Switching Characteristics
VCC e a 5.0V, TA e a 25§ C (See Section 3 for waveforms and load configurations)
54/74
Symbol
Parameter
Conditions
CL e 15 pF
RL e 400X
Min
tPLH
Propagation Delay
B to Q
tPLH
Propagation Delay
A to Q
tPLH
Propagation Delay
B to Q
tPHL
Propagation Delay
A to Q
tPLH
Propagation Delay
CD to Q
CX e 0 pF, RX e 5 kX
Figure 3-1, Figure a
CX e 0 pF, RX e 5 kX
Figure 3-1, Figure 3-10
tPHL
Propagation Delay
CD to Q
tw(out)
Pulse Width at Q with Zero
Timing Capacitor
CX e 0 pF, RX e 5 kX
Figure 3-1, Figure a
tw(out)
Pulse Width with External
Timing Components
CX e 1000 pF, RX e 10 kX
Figure 3-1, Figure a
Triggering Truth Table
Inputs*
Response
CD
A1
A2
B1
B2
L
X
X
H
X
K
K
K
X
L
X
H
X
X
L
H
X
X
X
H
No Trigger
No Trigger
No Trigger
Trigger
X
H
L
L
X
H
X
X
L
L
L
H
L
X
H
H
No Trigger
No Trigger
Trigger
Trigger
X
X
H
L
H e HIGH Voltage Level
L e LOW Voltage Level
X e Immaterial
*Input pins 1 and 2 are logically interchangeable, as are input pins 3 and 4.
3
3.08
Units
Max
28
ns
33
ns
36
ns
40
ns
40
ns
27
ns
65
ns
3.76
ms
Pulse Width vs RX and CX
TL/F/10212 – 3
Timing Capacitor CX –pF
TL/F/10212 – 4
FIGURE A
4
Physical Dimensions inches (millimeters)
14-Lead Ceramic Dual-In-Line Package (J)
Order Number 54122DMQB
NS Package Number J14A
14-Lead Molded Dual-In-Line Package (N)
Order Number DM74122N
NS Package Number N14A
5
54122/DM74122 Retriggerable Resettable Multivibrator
Physical Dimensions inches (millimeters) (Continued)
14-Lead Ceramic Flat Package (W)
Order Number 54122FMQB
NS Package Number W14B
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