UCC21520: UCC21520 opeartion at 4MHz with 20V and -5V power supply for half bridge

Hello Tahir,

Thanks very much for your message.

I think the major consideration of the UCC21520 is the maximum junction temperature. We have maximum recommended junction temperature is 130C.

To predict the junction temperature, we shall predict the power loss consumed by the IC only, see datasheet page 28. and utilize the following methods to predict the junction temperature:

Tj=Tc+RθJC*Pgd;

TC is the UCC21520 case-top temperature measured with a thermocouple or some other instrument, RθJC is the Junction-to-case-top thermal resistance from the Thermal Information table. Importantly, RθJA, the junction to ambient thermal impedance provided in the Thermal Information table, is developed based on JEDEC standard PCB board and it is subject to change when the PCB board layout is different.Tj is the junction temperature.

It is recommended to maintain the Tj<130C.

Btw, I don't know how the heatsink is mounted to dissipate the heat, and my only consideration is the mechanical issue which might put stress on the pins.

Can you please also advise us the part number of the FETs if possible?

Please feel free to let me know your comments and questions.

Wei

I am using MOSFETs C2M0280120D from Wolfspeed.