Other Parts Discussed in Thread: NE555
Dear all,
One of my customer has the follwing request:
When using the TLC555 in monostable mode as shown in the data sheet to stretch a pulse we are expecting an output pulse of 143 mS. (R = 130 K, C = 1 u, Vcc = 3.3 V).
The trigger input is a ve pulse of 500 nS and P.R.F of 20 Hz and amplitude 3.3 V.
On the PCB containing the 555 Timer we found that the output pulse was not as expected. The output pulse on pin 3 of the timer was found to be a mirror of the trigger pulse on pin 2 rather than the 143 mS pulse we expected.
A simulation of the circuit using simetrix software suggest that there is a minimum trigger pulse width of 6 uS below which the 555 does not function as a pulse stretching IC. This ties in with what has been seen on 2 separate PCBs. Can it be confirmed that this is the expected behaviour of the IC for the conditions?
regards,
Domenico