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National Semiconductor Electronic Components Datasheet

54121 Datasheet

One-Shot with Clear and Complementary Outputs

No Preview Available !

June 1989
54121 DM54121 DM74121 One-Shot with
Clear and Complementary Outputs
General Description
The DM54 74121 is a monostable multivibrator featuring
both positive and negative edge triggering with complemen-
tary outputs An internal 2kX timing resistor is provided for
design convenience minimizing component count and lay-
out problems This device can be used with a single external
capacitor Inputs (A) are active-low trigger transition inputs
and input (B) is an active-high transition Schmitt-trigger in-
put that allows jitter-free triggering from inputs with tran-
sition rates as slow as 1 volt second A high immunity to
VCC noise of typically 1 5V is also provided by internal cir-
cuitry at the input stage
To obtain optimum and trouble free operation please read
operating rules and NSC one-shot application notes careful-
ly and observe recommendations
Features
Y Triggered from active-high transition or active-low tran-
sition inputs
Y Variable pulse width from 30 ns to 28 seconds
Y Jitter free Schmitt-trigger input
Y Excellent noise immunity typically 1 2V
Y Stable pulse width up to 90% duty cycle
Y TTL DTL compatible
Y Compensated for VCC and temperature variations
Y Input clamp diodes
Y Alternate Military Aerospace device (54121) is avail-
able Contact a National Semiconductor Sales Office
Distributor for specifications
Functional Description
The basic output pulse width is determined by selection of
an internal resistor RINT or an external resistor (RX) and
capacitor (CX) Once triggered the output pulse width is in-
dependent of further transitions of the inputs and is a func-
tion of the timing components Pulse width can vary from a
few nano-seconds to 28 seconds by choosing appropriate
RX and CX combinations There are three trigger inputs from
the device two negative edge-triggering (A) inputs one pos-
itive edge Schmitt-triggering (B) input
Connection Diagram
Dual-In-Line Package
TL F 6538 – 1
Order Number 54121DMQB 54121FMQB
DM54121J DM54121W or DM74121N
See NS Package Number J14A N14A or W14B
Function Table
Inputs
A1 A2
B
L XH
X LH
XXL
HHX
HvH
vH H
vv H
L Xu
X Lu
H e High Logic Level
L e Low Logic Level
X e Can Be Either Low or High
u e Positive Going Transition
v e Negative Going Transition
e A Positive Pulse
e A Negative Pulse
Outputs
QQ
LH
LH
LH
LH
C1995 National Semiconductor Corporation TL F 6538
RRD-B30M105 Printed in U S A


National Semiconductor Electronic Components Datasheet

54121 Datasheet

One-Shot with Clear and Complementary Outputs

No Preview Available !

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
5 5V
Operating Free Air Temperature Range
DM54
b55 C to a125 C
DM74
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
Parameter
DM54121
Min Nom Max
DM74121
Min Nom Max
Units
VCC
VTa
VTb
VTa
VTb
IOH
IOL
tW
dV dt
Supply Voltage
Positive-Going Input Threshold
Voltage at the A Input (VCC e Min)
Negative-Going Input Threshold
Voltage at the A Input (VCC e Min)
Positive-Going Input Threshold
Voltage at the B Input (VCC e Min)
Negative-Going Input Threshold
Voltage at the B Input (VCC e Min)
High Level Output Current
Low Level Output Current
Input Pulse Width (Note 1)
Rate of Rise or Fall of
Schmidt Input (B) (Note 1)
45
5
5 5 4 75
5
5 25
14 2
14 2
V
V
08 14
08 14
V
15 2
15 2
V
08 13
08 13
V
b0 4
b0 4
mA
16 16 mA
40 40
ns
1 1 Vs
dV dt
Rate of Rise or Fall of
Logic Input (A) (Note 1)
1 1 V ms
REXT
External Timing Resistor (Note 1)
CEXT
External Timing Capacitance (Note 1)
DC
Duty Cycle (Note 1)
RT e 2 kX
RT e REXT (Max)
TA Free Air Operating Temperature
Note 1 TA e 25 C and VCC e 5V
14
0
b55
30
1000
67
90
125
14
0
0
40
1000
67
90
70
kX
mF
%
C
Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
VI
VOH
VOL
II
Input Clamp Voltage
High Level Output
Voltage
Low Level Output
Voltage
Input Current Max
Input Voltage
VCC e Min II e b12 mA
VCC e Min IOH e Max
VIL e Max VIH e Min
VCC e Min IOL e Max
VIH e Min VIL e Max
VCC e Max VI e 5 5V
IIH
High Level Input
VCC e Max
A1 A2
Current
VI e 2 4V
B
IIL
Low Level Input
VCC e Max
A1 A2
Current
VI e 0 4V
B
IOS Short Circuit
Output Current
VCC e Max
(Note 2)
DM54
DM74
ICC Supply Current
VCC e Max
Quiescent
Triggered
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
Min
24
b20
b18
Typ
(Note 1)
34
02
13
23
Max
b1 5
04
1
40
80
b1 6
b3 2
b55
b55
25
40
Units
V
V
V
mA
mA
mA
mA
mA
2


Part Number 54121
Description One-Shot with Clear and Complementary Outputs
Maker National Semiconductor
Total Page 6 Pages
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