Those are all the same* diode, just in different package.
- B330 in SMC
- B330A in SMA
- B330B in SMB
- B330C in SMC
* The only difference I've noticed so far (in Diodes Inc's datasheets) is a lower peak forward surge current (I_FSM) of 80A for the B330A,B and B330C compared to the 100A rating of the B330 (nothing).
I wonder why there is a difference in the Diodes Inc. datasheets between the spec for the B330 and B330C. I would have thought this spec difference would probably arise of the perhaps inferior thermals of the SMA/SMB packages, but why's the B330C's spec any different from the B330? Note, the B330B and B330C use the same datasheet... An error perhaps?
Turns out Diodes Inc. datasheets I've looked at do indeed mention 80A for the B330C, but another company, MDD, seems to say this too is good for 100A IFSM. Same method too! And they say it's the case for the B330B from them too... Same about the B330A actually. The I_FSM difference is likely a red herring. It's the same diode.