I'm having a problem with simple pulse generator circuit using LTC6993-1 (datasheet).

Circuit is not starting to pulse... This is my schematic and PCB layout: Schematic


I have checked the voltage levels and all of them are fine... I'm running it from 3V supply.

I don't know what I managed to get wrong with this simple circuit... Any ideas?


1 Answer 1


The circuit works as expected. The problem is probably your understanding of what a "Monostable Pulse Generator (One Shot)" is.

If TRIG is set to a fixed level you will never see any output.

The output goes high only if a rising edge is detected at TRIG and then it stays for a given time. That's what a monostable (one shot) does.

Maybe the confusion came from the fact that this IC contains an oscillator to implement the one-shot functionality by a digital counter.

  • \$\begingroup\$ So you are saying that I would need to change the "state" (bring the voltage from high to low) and then the circuit will start to oscillate? Is one trigger enough to keep the circuit oscillating indefinitely? \$\endgroup\$
    – StjepanV
    Feb 18, 2017 at 12:04
  • 1
    \$\begingroup\$ No, it will not "start to oscillate". It will just give one pulse of a defined length (that's why it's called "one shot"). It is not an oscillator! (and BTW: the sensitive trigger edge for type "-1" is 0-->1 (rising edge); not 1 -->0). Why did you assume it would oscillate? Nowhere in the datasheet it is suggested that it would oscillate. If it is triggered it gives one pulse; and if you want another pulse you have to trigger it again. \$\endgroup\$
    – Curd
    Feb 18, 2017 at 12:26

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