I've never smoked one, but I would suggest 250*F. Not sure about time, but couldn't take longer than 90 minutes?
Internal temps for beef tenderloin are 115-120*F for rare, 125-130*F for medium-rare, 130-140*F for medium. You might try cooking to 5-10*F below your target, then finishing at high heat to carmelize the outer surface.
This is a tender, lean cut of meat, so be careful not to overcook.
Regards,
Chris