Mosfet to case capacitance

swi

I am designing a three phase PFC converter and therefore the CCB032M12FM3 module does look attractive. While the typical mosfet to case dc short term isolation looks good, by design I am also sensitive to common mode currents. Do you have any information on the capacitance from different parts of the module to the case so that I may estimate the common mode currents involved with the large voltage swings on different mosfets? Or do you have an engineering sample (does not need to be perfect, but representative) so that I could determine this myself?

Also, the metal mounting tabs look to be part of the lead frame, though I assume still have the 3kV isolation. Would the capacitance to those tabs be any different than the remainder of the case?

Thanks

DanMartin

Hello swi,

The capacitance of the package is as follows:

DC+ to Case = 49.9 pF

DC-1 to Case = 6.6 pF

DC-2 to Case = 9.1 pF

DC-3 to Case = 7.7 pF

U to Case =20.3 pf

V to Case = 20.7 pF

W to case = 27.9 pF

The tabs are embedded in the plastic housing, but as soon as its bolted down to a heatsink, they are the same potential as the heatsink as well as the back side of the module when TIM is used.

swi

Thanks