12-03-2014 06:40 AM
I'm performing a stress analysis on a CCA containing several Virtex-5 FPGAs, specifically P/N XQR5VFX130-1CN1752V.
While reviewing the datasheets on the FPGAs I noticed that the Junction Temperature is considerably lower, 25 degrees C, than the storage temperature.
The majority of Mil-Spec ICs that I have worked with have a higher Tj than Tstorage. I wanted to make sure this information is correct because the lower Tj causes the part to fail derating. Thanks for any help with this.
12-03-2014 08:04 AM
Somewhere, you have pulled the wrong value for junction temperature, 25C, from the data sheet if you read it as 25C. The maximum junction temperation as Virtex-5Q part that you are using is documented in DS714 Table 1 as 125C. The storage temperature always exceeds the operating junction temperate as the device is not under electrical stress at the same time and is also in the same table as -65 to 150C.
12-03-2014 08:27 AM
I think he meant that 25 degrees was the difference between the operating and storage temperature. I'm not sure what sort of parts he uses that allow the junction to be higher than the storage temperature, but in most advanced CMOS parts the static power dissipation (leakage) at higher temperatures would tend to limit the maximum junction temperature under operating conditions.
12-03-2014 08:53 AM
Discussion of the Q5 device issues should not be on the public forums.
Please work with your assigned A/D FAE.