Hi Everyone,

I am trying to design a measurement system (capacitive divider) for signals with frequency content up to 100MHz, however, I am struggling to find suitable capacitors with suitably low ESL. Even a few nH (10nH in LV part of divider C4 below) causes oscillations when excited by an exponential rise (due to self-resonance?) or a high initial spike when including a series resistor in an attempt to damp the oscillations. I have attached an image of the spice circuit and results. Does anyone have any suggestions on how to mitigate this issue, or suggest a very good high-frequency capacitor (require 50-100nF, very high dV/dt, voltage rating >100V).

View attachment 156330

Thank you in advance

Jon

I am trying to design a measurement system (capacitive divider) for signals with frequency content up to 100MHz, however, I am struggling to find suitable capacitors with suitably low ESL. Even a few nH (10nH in LV part of divider C4 below) causes oscillations when excited by an exponential rise (due to self-resonance?) or a high initial spike when including a series resistor in an attempt to damp the oscillations. I have attached an image of the spice circuit and results. Does anyone have any suggestions on how to mitigate this issue, or suggest a very good high-frequency capacitor (require 50-100nF, very high dV/dt, voltage rating >100V).

View attachment 156330

Thank you in advance

Jon

Last edited: