IEC 63378-2-1:20 24规定了分立半导体封装（TO-243、TO-252和TO-263）的三维（3D）热模型，用于电子器件的稳态热分析，以准确估计结温。 该模型假设由半导体供应商制造，并由电子设备的组装制造商使用。

IEC 63378-2-1:2024 specifies three-dimensional (3D) thermal models of discrete semiconductor packages (TO-243, TO-252 and TO-263), utilized in the steady-state thermal analysis of electronic devices to estimate junction temperatures accurately.
This model is assumed to be made by semiconductor suppliers and to be used by assembly makers of electronic devices.