URGENT: Forgot the thermal pad of ADAU1452. What now?
Thread Summary
The user inquired if the ADAU1452 would function without a thermal pad connection to the ground plane. The support engineer confirmed that the IC will operate without the electrical connection but warned that it may overheat at ambient temperatures above 60°C, potentially exceeding the maximum junction temperature of 125°C. The user successfully tested the design with thermal grease and confirmed the PLL is now working.AI Generated Content
Hello,
I just started to work on a PCB for the ADAU1452. However, I forgot to place the thermal pad on the footprint I created, so no electrical connection exists between the pad and the ground plane. Will the part work? As far the heat goes, we can improvise. But I need to know, will this IC will need the "electrical" connection on the pad in order to run at all?
Thank you.
Audio Signal Processors
adau1452
SigmaDSP Audio Processors
Hello,
We run it here in the lab with a socket that has no connection to the EP so I know it is not required for operation.
With no thermal pad it WILL overheat when running a full program under hot conditions especially if you happen to get a part from a lot that has slightly faster silicon formulation. I think the theta-ja is around 38 degrees C/Watt with no heatsink. So that means that if you are running ambient temp over ~60deg C the junction temperature will exceed 105C. The MAX junction temp is 125C so ambient over ~80C is a problem.
So you certainly can use these boards to evaluate your design and work out the kinks but for production units that may be operating in the desert southwest in the sun will be a problem.
I have recently done some lab experiments using a socket and I exceeded a die temp of 120C very easily with fast slew material. I was able to run it at ambient temperatures but at 85C it was over 120C. The thermal diode measurement IC on the eval board maxed out at 120C.
So anyhow, that is the answer to your question.
Dave T
Dave, thank you for your fast reply and I hope you are well!
As long as we can test the design, I'm happy with it as we will spin a second version of this PCB in a month. I tried running it with SigmaStudio and the PLL is not locking. I will look over my schematic again and see if I find any problems. If I need help with this different matter, should I start a new thread?
Thanks again.
Dave, it's all good now, including the PLL. Thank you for your help.
Hi Dave,
I thought it would be interesting to show the thermal image of my DSP running with some thermal grease underneath, without the soldered pad. It is running 4 sine generators, driving all outputs, so the core demand is little, but at least we know it doesn't overheat quite so easily at the bench. Thanks again for helping with my questions.
Please log in to reply.