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# CDCV304PW maximum operating junction temperature

Other Parts Discussed in Thread: LMK1C1104
Another, similar, question:  absolute junction temperature for CDCV304PW is 125 in datasheet and the recommended operating ambient is 85C.  The Tj is for stress screening. Please provide maximum operating junction temperature is where full functionality is implied? Thank you.
• Please provide the junction temperature where full functionality is implied

• Hi Su Mun,

Junction temperature is the maximum temperature on the IC where it needs to operate with proper functioning. While ambient temperature is the outside environmental temperature on the package. There are thermal resistor parameters listed in the datasheet which helps with calculation of junction temperature with respect to ambient temperature.  It include the power dissipation of the IC as well.

Here is good resource to understand both  and calculate the junction temperature with respect to ambient temperature and power consumption of the IC. Note that junction temperature is on the higher with respect to ambient so that's why the ambient specification is lower.

Total functionality for junction temperature  = ambient temperature of 85C + Power consumption of IC x R theta

You want to make sure that all the parameter combined on the right side should not exceed the junction temperature of the IC listed in datasheet.

https://www.ti.com/video/5841048435001

I hope this answers your question. Let me know if you have further queries.

Best,

Asim

• can you please check with your design team and find the maximum junction temperature where full functionality is guaranteed?  This could be in a vacuum with no air and mounted to a cold plate, to just give you a different perspective.

• Hi Su Mun,

I had a chat with the design team and since this is an old part so design database is difficult to find. Based on the electrical specification table which is specified for 85C ambient temperature unless otherwise noted in test conditions. You can estimate that all those electrical characteristics were met at about junction temperature of about 100C taking into account the power consumption.

Part will be functional at 125C but then the performance is not characterize at that temperature as I mentioned above.

You can use a P2P LMK1C1104 part, which had a ambient temperature of 125C. So you can expect that its electrical specification are fully specified at that junction temperature.

Best,

Asim