Q
For carrying out the analysis the following part specifications are necessary:
1)Power Dissipation (W)
2)Junction Temperature (TJ)
3)Case Temperature (Tc)
4)Junction to ambient thermal resistance (θJA)
5)Junction to case thermal resistance (θJC)
6)Case to Ambient thermal resistance (θCA)
A
ADP3339AKCZ-3.3-R7:
We do not have much of the data requested since the ADP3339 was designed over
10 years ago.
The maximum power dissipation will be dependent on the ambient temperature and
can be derived based on the thermal resistance Theta-ja and max junction
temperature of 150C. For example, if the ambient temperature is 50C, the
maximum power dissipation will be (150C-50C)/62.3C/W = 1.6W
Similarly, the maximum case temperature will be set by the ambient temperature
and power dissipation. Therefore, assuming a 50C ambient, Tc =
50+1.6W*26.8C/W = 92.9C
Theta-ja and Theta-jc are in the ADP3339 DS and are 62.3C/W and 26.8C/W
respectively
I do not have a value for Theta-ca and this would require requesting a thermal
simulation from the packaging house. This typically costs about $5K and takes
about 6weeks which is why we usually don’t request this data for old designs.
The maximum power dissipation and case temperature can be derived from the DS
data in the same way as the ADP3339.
