A few applications work at extreme temperatures, either very low (70K, -193°C) or very high (300°C). Under such temperatures, the standard electrical simulation models are not valid anymore as some side effects occur, including variation of transistors threshold, low-temp carrier mobility, and high-temp junction reverse leakages. We handle such application constraints by extending the device modeling based on “test vehicles” (specific chips integrating all the process devices). These devices are electrically measured under the conditions corresponding to the targeted temperature range. From the measurements are generated sets of new equations which will operate the “extended” electrical models. By using the newly-created model library, the ASIC design can be simulated though the extended temperature range.