[SOLVED] Self-Heating Test for Multilayer Ceramic Capacitor

[chiques]

Hello Community,

I’m trying to verify the I^2R ripple of my circuit. I tried heating this 7676C capacitor up using NXP’s MRF300AN-13MHZ in a straight thru 50 Ohm configuration, but the capacitor doesn’t even tick up 1 deg C. I ran the amplifier all the way up to 300W+, monitored my reflection and Pout to make sure there weren’t any mismatch issues but the cap is still basically at room temperature.

Any ideas as to why I can’t heat this capacitor up using the 300W RF signal?

 

[FvM]

Presuming the specified ESR of 7 mOhm would be valid for 13 MHz, expected losses @300W are 42 mW. However ESR at 13 MHz is probably smaller than at 30 MHz. No big heating expectable.

 

[crutschow]

Do you not understand what ESR is?

 

[D.A.(Tony)Stewart]

The Q is > 2000 so the real power loss is < 1/2000 of apparent power

 

[biff44]

i would put a 3 dB attenuator at the amp output. then i would reconfigure the capacitor to add an inductor to make a 13 MHz resonator with a high Q. Then i would drive that resonator. Be careful, there may be very high voltages across the cap

 

[D.A.(Tony)Stewart]

10nF is about 1 Ω at 13 MHz and limited in current by Rs + RL = 100Ω.
Dissipation is only 1/Q (Q>2000) of applied power, so theory matches measured near null T rise.
SRF >> 13 MHz.

Meanwhile 10nH will resonate with 10nF near 15 MHz so parasitic ESL must be low using 0.5nH /mm or so with 50 ohm traces.

 

[chiques]

Reconfiguring it in shunt with an inductor did the trick. I was able to heat it up 25C from room temperature with ~8W.
Thanks everyone.