I have a input power filter circuit.
It has ESD Protection capacitors which help to protect the downstream circuit from ESD Pulses.
ESD Capacitors Specifications :
C0001, C0002, C0003, C0004 = 47nF, 100V, 10%, 0805
My ESD Pulse Specifications :
Contact Discharge : +/-4kV & 150pF / 330Ohms
Contact Discharge : +/-8kV & 150pF / 330Ohms
Air Discharge : +/-15kV & 150pF / 330Ohms
Can someone please help me on how to do the calculations so as to justify that my capacitance value and voltage ratings of the capacitors are within the limits designed.
My understanding :
For example, I take the +/-4kV & 330pF spec
4kV * 150pF = 600nC
This Charge will then get to the input ESD Capacitors :
600nC / 47nF = 12.76V (And in this step, should I consider the capacitance value for the single cap 47nF or should I consider the equivalent series capacitance value of 23.5nF)
So, My voltage rating of the capacitor 100V > 12.76V is appropriate for this pulse.
Is my approach correct?
My questions :
The above calculation I have done for only positive 4kV. Can someone help me on how to understand when negative 4kV is applied and how to go about the calculation.
And I have justified only for the capacitance voltage rating. How to justify for the capacitance value? Can someone help me with the formula to justify the capacitance value?