Nano second delay pulse train generation circuit using 74LS123 IC

For some applications we need to generate a trigger signal which is in nanoseconds width range. For example, you want to trigger a camera immediately after an event and keep the exposure time minimum to get the best possible image.

I needed this circuit for similar application. Requirement was to get pulse width of the order of tens of nanosecond. For this purpose I used 74ls123 which a dual retriggerable monoshot IC.

The schematic was prepared and simulation result gave pulse width down to 10 ns.

However when the circuit was fabricated, even with different combination of R and C, we could not get pulse width lower than 60 ns. This may be due the parasitic capacitance of the wires and solder.