The SPM25 series has all the same features and functionality of the SPM15, but offers 25W of output power from a narrower 2:1 input voltage range of 36-75V. Three output voltages are available, 3.3V, 5V, and 12V. The narrower input voltage range results in higher efficiency, which consequently allows greater power in the same 1” x 1” package. The power density for any given package size is based on the amount of heat that the package must dissipate, which is calculated from the output power and efficiency.