I am using the LP38693SD-3.3/NOPB linear regulator from TI. In the datasheet of the IC under 9.2 Typical Application>Output Capacitor it says I need a ceramic capacitor with an ESR between 5mOhms and 500mOhms(I assume at 100kHz). Because a capacitor has capacitance, resistance and inductance (see first screenshot) I tried to calculate the ESR of the capacitor using the formula for the impedance of a RLC circuit(see second and third screenshot) where I approximated XL = 0 because from what I understood MLCC are specially designed to have a very small inductance and their impedance is primarily resistive(ESR) and capacitive(XC) (I am not sure, I might be wrong). So I chose a random capacitor from Murata in order to be able to use their design support software SimSurfing from which I acquired the impedance and capacitance at 100kHz(see screenshot 4 and 5). For my capacitor which has a ~3.2 Ohms impedance and a ~0.5uF capacitance at 100kHz I get an ESR equal to ~0.346 Ohms. The problem is when I look at the graph of the frequency and impedance if I hold the cursor on the 0.1MHz line and I move it just a little bit I can get 3, 3.1 and 3.2 Ohms at 0.1MHz, which depending on which one you chose you will get a completely different value for the ESR. I am completely lost, please help!
