Part # 74LS221 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: DM74LS221 Dual Non-Retriggerable One-Shot with Clear and Complementary Outputs

Part Details:

DM74LS221 February 1992 DM74LS221 Dual Non-Retriggerable One-Shot Dual with Clear and Complementary Outputs General Description Y Pin-out identical to LS123 (Note 1) Y Output pulse width range from 30 ns to 70 seconds Non-Retriggerable The DM74LS221 is a dual monostable multivibrator with Y Hysteresis provided at (B) input for added noise Schmitt-trigger input Each device has three inputs permit- immunity ting the choice of either leading-edge or trailing-edge trig- Y gering Pin (A) is an active-low trigger transition input and Direct reset terminates output pulse pin (B) is an active-high transition Schmitt-trigger input that Y Triggerable from CLEAR input allows jitter free triggering for inputs with transition rates as Y DTL TTL compatible slow as 1 volt second This provides the input with excellent Y Input clamp diodes noise immunity Additionally an internal latching circuit at the Note 1 The pin-out is identical to LS123 but functionally it is not refer to input stage also provides a high immunity to VCC noise The Operating Rules 10 in this datasheet clear (CLR) input can terminate the output pulse at a prede-termined time independent of the timing components This Functional Description (CLR) input also serves as a trigger input when it is pulsed The basic output pulse width is determined by selection of with a low level pulse transition ( ) To obtain the best an external resistor (RX) and capacitor (CX) Once triggered and trouble free operation from this device please read op- the basic pulse width is independent of further input tran- One-Shot erating rules as well as the NSC one-shot application notes sitions and is a function of the timing components or it may carefully and observe recommendations be reduced or terminated by use of the active low CLEARinput Stable output pulse width ranging from 30 ns to 70 Features seconds is readily obtainable Y A dual highly stable one-shot Y Compensated for VCC and temperature variations

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74LS221.pdf Datasheet