How can it be (from other post):
The junction-to-case top thermal resistance for the ADS7883SBDBVT is 54.3 °C/W. The junction-to-board thermal resistance is 35.3 °C/W.
when thermal impedance in the data sheet is 295.2 °C/W?
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How can it be (from other post):
The junction-to-case top thermal resistance for the ADS7883SBDBVT is 54.3 °C/W. The junction-to-board thermal resistance is 35.3 °C/W.
when thermal impedance in the data sheet is 295.2 °C/W?
Hello Magnus,
The thermal impedance in the datasheet is the junction to ambient, which takes into account the thermal properties of the SOT23 package as well as the properties of a standard test PCB. R-theta-ja is the least accurate number when used to predict thermal performance since there is a wide variation in actual PCB construction, but can be a good starting point, or figure of merit.
Take a look at the following application note for a definition of the different thermal metrics.
http://www.ti.com/lit/an/spra953c/spra953c.pdf
Regards,
Keith N.
Precision ADC Applications