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→Estimating CPU junction temperature (Tj)
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== Estimating CPU junction temperature (Tj) ==
The processor doesn't allow for measurement of the junction temperature, thus use of some indirect method is required, as described in the [[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/spra953bspra953c), allows for estimation of the junction temperature Tj. The PsiJT and the θjc parameters identified in the AN 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.
=== Using the current/power monitor ===
=== Using the PMIC ===
The PMIC TPS659113 mounted on Naon provides Thermal shutdown protection and hot-die detection functions. These functions refer to the PMIC junction temperature and not to the CPU Tj, but they can be used to implement some protection/detection strategies.
===Using a contactless sensor on carrier board===
Another option for measuring the CPU's case temperature is the use of a contactless sensor that can be mounted on carrier board. See for example: http://www.ti.com/product/tmp006.
== Analisys suggestions ==
