Hi,
I have to insert the component Zetex ZDT749 (datasheet http://www.diodes.com/datasheets/ZDT749.pdf), which is a dual pnp transistor, in the reliability prediction tool. The datasheet says that the package is SM-8 (8 lead SOT223) but I can′t find this package on the FIDES guide. I think the best solution is to divide the component into two pnp transistors and to calculate the rise of the temperature with the total power consumption and the thermal resistance given on the datasheet, but then which package type should I choose for every single transistor?
Thank you
Enea
The SOT223 package is in the FIDES Guide (page 121, "of course" I refer to 2009 edition - OK, its page 68 in 2004A edition).
The natural modelisation is therefore to take a SOT223 package with 2 transistors inside (much simplier is not possible!). The way to manage 2 transistors in the same package was not clarified on the page 69 of the 2004A edition (this explanation is a bit lost in this document), but it is now clearly written page 123 of the 2009 edition.
What is not in the FIDES Guide is a thermal resistance for SOT223 with 8 pins. So you have to assess the thermal resistance with another method.
I hope it helps!
Lambda