ADS7883: Junction to Case

Magnus Larsson54

Part Number: ADS7883

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?

over 5 years ago

0 Magnus Larsson54 over 5 years ago

Prodigy 40 points

This was the original question: e2e.ti.com/.../726647

0 Keith Nicholas over 5 years ago in reply to Magnus Larsson54

TI__Mastermind 36150 points

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

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ADS7883: Junction to Case