TLC2252A - Maximum Operating Temperature and Failure Rate

Hi,

what do you mean by "very high failure rate"? Do you have any numbers?

Doing a similar calculation as shown in this link

https://e2e.ti.com/support/audio-group/audio/f/audio-forum/787885/opa1652-operating-junction-temperature-for-opa1652/2924570#2924570

with the TLC2252AID, gives a MTBF of 8550 years when operating the TLC2252AID nine hours a day at a junction temperature of 130°C.

Is this what you see?

Please note that the junction temperature can rise well above 130°C ambient temperature when the chip has to dissipate power because of driving a heavy load. This will additionally decrease the life time.

Keep in mind that fast temperature changes can stress the chip more than a constantly high temperature. This the more the faster the temperature changes occur. So does the TLV2252AID undergoe a thermal shock during each temperature cycling? This should be avoided in any case because it can dramatically decrease the life time.

Also, the maximum temperature of printed circuit boards made of FR4 is 100°C. At higher temperatures FR4 can show abnormal thermal expansion which can additionally  stress the OPAmp and decrease the life time.

And finally, the soldering process can also have a massive impact on the life time, if the recommended soldering temperature profile is violated.

Kai 

Hi,

It looks like Kai covered the questions about your TLC2252AID failure rate, conditions and temperature cycling. Besides those questions what type of failure is it you are experiencing; a parametric shift, or a complete electrical failure?

Regards, Thomas

Precision Amplifiers Applications Engineering

Hello Kai

Thank you very much and appreciate the feedback and advice.

1. The current failure rate is at about 2% a month or about 500 of this parts being found faulty every month.

2. Noted on the MTBF as shown above.

3. Noted on the junction temperature being able to rise well above 130°C ambient temperature when the chip has to dissipate power because of driving a heavy load. This will additionally decrease the life time.

4. The TLV2252AID in use does goes under a thermal change from room temperature of ~25C to 125C at an interval of 30 minutes for 3 times a day during each temperature soak at 125C that last for 3 hours each (3 cycles x 3 hours each = 9 hours daily).Can this be a cause of concern ? 

5. Noted on the printed circuit boards material.We are using polymide VT90H with a higher temperature resistance so we believe this should not be the cause of the problem.

6. Noted on the soldering process - checked with our PCB fab. and they say it complies with the parts requirements and should not have any issue from this.

Hello Thomas 

Appreciate the help.Problem that i have with this component is mostly electrical failure.

Thank you

Prem 

Hi Premsinivasu,

Thomas rised an important question: What is the type of failure at all?

100°C / 30min = 3.3°C / min. Such a change rate of temperature should not be a problem, provided the temperature change occurs evenly, or by other words, if the change rate is constant 3.3°C / min during the whole temperature change from 25°C to 125°C. Ovens can usually be programmed to perform an even ramp.

But if you only turn-on the oven and the oven starts to heat-up with full power, then the chips would not see an even temperature ramp and the maximum change rate can be very much higher. And if your oven even shows overshots when regulating, then the chips will see a very much higher stress.

Have you measured the temperature profil of oven? Are there even ramps?

Also, what about the cooling? Are the chips cooled down by the same (even) change rate of 3.3°C / min?

Another issue is: Even harmless temperature cycling can become a problem, if the chip sees too many of them. How many months are the chips temperature cycled in this way?

Kai