To elaborate on this a bit. Let’s think about a standard 0602 sized part - that’s 0.06” long or about 1.5 mm. A piece of wire that long has an inductance of about 1.5 nH.
With, say, 33 pF, that’s resonant at 715 MHz. And yet, such parts are regularly used in all sorts of circuits at higher frequencies. You just design for the parasitic values.
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On Apr 2, 2025, at 20:14, Jim Lux via groups.io <jimlux@...> wrote:
?The max frequency is probably more about where losses get too big.
And they’ll measure for a very wide range. Most design tools can deal with staying away from the SRF, if supplied with the part parameters.
After all, at microwave frequencies most parts have a very complex and varying impedance.
On Apr 2, 2025, at 15:34, Brian Beezley <k6sti@...> wrote:
?By coincidence, I just added an image showing capacitance and dissipation factor plotted by my S-parameter plotter. It was derived from an .s2p file provided by Kyocera. Scroll to the last image:
One thing I don't understand. Manufacturers specify useful frequencies several times the capacitor self-resonant frequency, as revealed by the .s2p files they supply. The 33 pF shown departs from 33 pF as it approaches its 1.6 GHz SRF, which is nowhere near the 10 GHz specified upper frequency limit. All the capacitor manufacturers seems to do this. Why?
Brian
