Rth(j to mb) for part BUK9Y12-40E

The thermal resistance for this part (Rth(j - mb)) appears to be in units of “K/W”, assuming Kelvin.

Is this a typo or should it read “C/W” i.e. Celsius?

Thank you,

The unit would indeed refer to degrees Kelvin, but in context it’s interchangeable with celsius, since it’s referring to a temperature change/interval.