Hey,
i got tasked to find a replacement for this Transistor even tho i got 0 clues about electronics. The engineer told me he would need ART40U120 I can find data sheets for it but its not possible to order it from anywhere. Maybe someone here could help me 
Its for a replacement im a solar power inverter. Thanks in advance! :))
Peteeee21
Thank you for contacting DigiKey , sorry I am not seeing that we have this part or a replacement to offer for it . I am not sure where you can get this transistor .
Thanks Craig
Allright! Thanks for ur fast reply either way i appreciate the effort !
Hi Peteeee21,
I didn’t find any parts that looked like a drop-in replacement, but the parts in the below link are somewhat similar. No guarantees that any of them would work in your particular application, but one of these might be reasonable to try if you need to get something and you haven’t found that exact part.
APT33GF120BRG is parametrically similar in many respects and may be an option worth considering, however it is not a direct replacement.
This resource does a nice job of explaining the various attributes of the part family and their significance, and may prove helpful/informative.