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DM74122 Datasheet, PDF (1/6 Pages) National Semiconductor (TI) – Retriggerable Resettable Multivibrator
June 1989
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 out-
put 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 trigger-
ing 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)
Where tw is in ns RX is in kX and CX is in pF
Connection Diagram
Logic Symbol
Dual-In-Line Package
TL F 10212 – 1
Order Number 54122DMQB 54122FMQB or DM74122N
See NS Package Number J14A N14A or W14B
VCC e Pin 14
GND e Pin 7
NC e Pins 10 and 12
Pin Names
A1 A2
B1 B2
CD
QQ
Description
Trigger Inputs (Active Falling Edge)
Trigger Inputs (Active Rising Edge)
Direct Clear Inputs (Active LOW)
Outputs
TL F 10212 – 2
C1995 National Semiconductor Corporation TL F 10212
RRD-B30M105 Printed in U S A