54122

54122 DM74122 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 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) Where tw is in ns RX is in kX and CX is in pF Connection Diagram Dual-In-Line Package Logic Symbol TL F 10212 – 2 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 Q Q Description Trigger Inputs (Active Falling Edge) Trigger Inputs (Active Rising Edge) Direct Clear Inputs (Active LOW) Outputs C1995 National Semiconductor Corporation TL F 10212 RRD-B30M105 Printed in U...