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The processor doesn't allow for measurement of the junction temperature, use of some indirect method is required, as described in the following : http://wiki.dave.eu/index.php/Power_%28Naon%29[[Power (Naon)]] section. Here you can find useful information related to the thermal characteristics of the package, (extracted from the CPU datasheet) , that, together with the contents of the TI application note "Semiconductor and IC Package Thermal Metrics" (http://www.ti.com/litv/pdf/spra953b), allows for estimation of the junction temperature Tj. The PsiJT and the θjc parameters identified in the AN, which are the most important ones to identify the difference between the external case temperature (which is easily measurable), and the internal junction temperature. Once this value is known, it is possible to determine the highest acceptable environment temperature to avoid reaching critical junction temperature.

A Obtaining an accurate measurement of power consumption for the CPU (required for this kind of assessment) is not easy. However, as a first estimate, you can use the power monitor INA226A mounted on the NaonEVB-Mid carrier board, which allows for measurement of the CPU module global absorption (we consider negligible the part due to the electronics external to the CPU). Please refer to http://wiki.dave.eu/index.php/[[NELK_Power_Management#Measurements_script ]] for details on how to perform the measurement. Once you've collected the data, you can compare it with the ones we've reported on http://wiki.dave.eu/index.php/Power_consumption_%28Naon%29[[Power consumption (Naon)]].