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Aranion
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Hi. I am quite confused why Rdson has positive temp coefficient when semiconductors has negative temp coefficient. What's happening to the channel when temperature increases?
RDSon, or on-resistance, is the resistance of a transistor when it is in the on state. This resistance is affected by the temperature of the transistor. As the temperature increases, the resistance of the transistor also increases. This is known as a positive temperature coefficient, meaning that the resistance increases as the temperature increases.
The positive temperature coefficient of RDSon is caused by changes in the mobility of charge carriers in the transistor. As the temperature increases, the mobility of these charge carriers decreases, resulting in an increase in resistance.
The positive temperature coefficient of RDSon can affect the performance of a transistor in several ways. As the resistance increases with temperature, the transistor may not be able to handle as much current, which can limit its power handling capabilities. It can also affect the accuracy and stability of the transistor's output.
While the positive temperature coefficient of RDSon can have negative effects on transistor performance, it can also have some benefits. For example, it can act as a self-protective mechanism, as the resistance will naturally increase at higher temperatures, preventing the transistor from overheating. This can also help with thermal management in electronic circuits.
There are methods that can be used to reduce or eliminate the positive temperature coefficient of RDSon. One way is by using different materials or designs for the transistor, such as using a different type of semiconductor or implementing additional structures within the transistor to compensate for the temperature effects. Another approach is to use external circuitry, such as a negative feedback loop, to offset the temperature effects on RDSon.