what topology do you use for extremely high frequency dynamic loads? whats the road map look like?
What is extremely high frequency 1MHz, 100MHz, 10GHz?
If you go into the MHz your wirering begins to behave as transmission lines with impedances that are frequency dependant and a lot higher than dc resistance.
There it starts to become a whole different design.
I watched a few teardowns of the commercially available DC loads ... the BK Precision 8500 uses IRFP250N as the power mosfet. checking the datasheet, there's no SOA mentioned which makes everyone jump to the conclusion that they're not rated for linear applications
Obviously BK Precision doesn't just use random parts and have done their own testing to make sure that this mosfet meets their requirement. How can somebody know if the part is suitably rated without destructive testing?
The more I dig into this subject the more confused I am as to which part performs the best for a given price budget ...
I stumpled over this too.
You can bet a dollar they tested this and perhaps they have a test method to sort them.
If the part is not rated for linear mode this does not exclude it per se, the manufacturer did not test nor garanties a SOA at DC.
And as you can see, there are quite an amount of them in parallel that would suggest a higher power rating...
There are few modern mosfets with linear mode SOA in datasheet and they all suffer from not giving SOAs for other die temperatures than 25°C.
There is one exception I know: IXYS has a series of linear rated MOSFETS that give another SOA for more convenient 75°C (I hopefully remind correctly).