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LMC555

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SNAS558M – FEBRUARY 2000 – REVISED JULY 2016

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Device Functional Modes (continued)

Top Trace: Input 5 V/Div.

TIME = 0.1 ms/Div.

Middle Trace: Output 5 V/Div.

Bottom Trace: Capacitor Voltage 2 V/Div.

C = 0.01 µF

Figure 4. Monostable Waveforms

Reset overrides Trigger, which can override threshold. Therefore the trigger pulse must be shorter than the

cycle when the output is high, the further application of a trigger pulse will not effect the circuit so long as the

trigger input is returned high at least 10 µs before the end of the timing interval. However the circuit can be reset

during this time by the application of a negative pulse to the reset terminal. The output will then remain in the low

state until a trigger pulse is again applied.

triggering. Figure 5 is a nomograph for easy determination of RC values for various time delays.

NOTE

In monstable operation, the trigger should be driven high before the end of timing cycle.

Figure 5. Time Delay