GLITCHOUT waveform is not in square shape and doesn't fully drive the MOSFET

I captured the glichted VCC and GLITCHOUT during voltage glitching attack.

  • Chan 1: glitched VCC
  • Chan 2: trigger
  • Chan 3: clock
  • Chan 4: GLITCHOUT

As you can see both the glitched VCC and GLITCHOUT don’t have straight edges and are bouncing a lot. VCC doens’t even drop to 0V, probably because the GLITCHOUT doesn’t have enough drive to pull the MOSFET.

To verify it, I disconnected the glitch signal between the two boards, and did a trace again:

The GLITCHOUT above is still having a bad shape. Is there anything I can do to improve it?


It’s expected that you don’t see straight edges for the glitch out waveform. There’s a bunch of parasitic capacitance and inductance from the FPGA leads, the traces, the MOSFET input, etc. that don’t have much of an effect at lower frequencies, but come into play when you’re at this time scale. It’s the same case for the Vcc rail. For example, changing the length of the cable between you and the target has a large effect on what the glitch wave looks like.