Push pull oscillator

Did you calibrate your scope probes ? Ground lead on probe very short ? Probe
set to X10 (if your scope does not auto detect probe setting) ?




Regards, Dana.

The circuit you show is not really suitable for building with discrete components, or for voltage level translation.

Both FETs will be turned on briefly during each input transition, and with the input only reaching 3.3V the upper FET may be permanently conducting to some extent.
The upper FET will also be receiving a rather higher gate-source voltage when on, which could explain the overshoot?

Some of the pulse on the scope could also be capacitive feedthrough internally to the FETs, plus the dive asymmetry?

(I don't think it's a scope artefact, as they are usually symmetrical & there is no negative overshoot at all).

Add some decoupling capacitors across your Vdd and ground pins one 0.1uF ceramic and a larger 10uF or bigger electrolytic. Then make sure your probe is set up correctly as suggested above.

rjenkinsgb said:

I don't think it's a scope artefact, as they are usually symmetrical & there is no negative overshoot at all

Click to expand...

Which makes me think the N-channel Isn't getting turned on fully to get back to ground quickly.