SN74CB3Q3251: Junction temperature

Hi Chong,

I have just released an FAQ on this topic - as the process for every switch is the same.

The link is here: https://e2e.ti.com/support/switches-multiplexers-group/switches-multiplexers/f/switches-multiplexers-forum/1063078/faq-how-to-calculate-the-max-junction-temperature-of-an-analog-switch-multiplexer

It includes a calculator to help calculate the max temperature as we typically don't provide max junction temperature as a spec for analog switches and multiplexers, because the large majority of the analog switch and multiplexer portfolio at TI (the SN74CB3Q3251 included) will never reach a junction temperature that is dangerous for the part if the datasheet is followed. However you can estimate the max temperature it will reach during operation - the FAQ I linked explains how it is done as well as providing an excel tool to help calculate so it doesn't have to be done manually. 

If you have any other questions please let me know!

Best,

Parker Dodson