器件名称:
DM74LS221N
功能描述:
Dual Non-Retriggerable One-Shot with Clear and Complementary Outputs
文件大小:
142.7KB 共6页
简 介:
DM74LS221 Dual Non-Retriggerable One-Shot with Clear and Complementary Outputs February 1992 DM74LS221 Dual Non-Retriggerable One-Shot with Clear and Complementary Outputs General Description The DM74LS221 is a dual monostable multivibrator with Schmitt-trigger input Each device has three inputs permitting the choice of either leading-edge or trailing-edge triggering Pin (A) is an active-low trigger transition input and pin (B) is an active-high transition Schmitt-trigger input that allows jitter free triggering for inputs with transition rates as slow as 1 volt second This provides the input with excellent noise immunity Additionally an internal latching circuit at the input stage also provides a high immunity to VCC noise The clear (CLR) input can terminate the output pulse at a predetermined time independent of the timing components This (CLR) input also serves as a trigger input when it is pulsed with a low level pulse transition ( ) To obtain the best and trouble free operation from this device please read operating rules as well as the NSC one-shot application notes carefully and observe recommendations Y Y Y Y Y Y Y Pin-out identical to ’LS123 (Note 1) Output pulse width range from 30 ns to 70 seconds Hysteresis provided at (B) input for added noise immunity Direct reset terminates output pulse Triggerable from CLEAR input DTL TTL compatible Input clamp diodes Note 1 The pin-out is identical to ’LS123 but functionally it is not refer to Operating Rules 10 in this ……
