LMC555: Confirm basic operations of two cases on Monostable operation

Motoyasu Hattori

Part Number: LMC555

Hi,

On monostable operation,

During output is High, additional trigger is ignored. In other words, Red Trigger pulses are ignored. Is it correct? Please let me know.

On the other hands, when trigger pulse is longer than output pulse, the following waveform is correct operation, because Trigger is only falling pulse timing. Is it correct? Please let me know.

Thanks and best regards,
M.HATTORI

over 5 years ago

0 Ron Michallick over 5 years ago

TI__Guru**** 164476 points

Hello Hattori-san,

Trigger pulses that happen when output is already high are honored but have no effect on output (stays the same) or timing cap (continues to charge normally), so first waveform is correct.

The trigger low pulse must end before the output high pulse otherwise the output high pulse will be extended, so 2nd waveform is incorrect.

The trigger input is level sensitive, not edge sensitive.

See edge triggering section in monostable FAQ https://e2e.ti.com/support/clock-and-timing/f/48/t/857914

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LMC555: Confirm basic operations of two cases on Monostable operation