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OPA2134: OPA2134 running hot

Part Number: OPA2134
Other Parts Discussed in Thread: TL072

Hello to everybody,

New on this forum, i hope that someone will be able to help me.

So, I meet en issue with that AOP (OPA2134) that i don't understand... it is running hot. I mean, really hot, even on idle state.

Here is the context; i have designed a preamp which uses TL072 AOPs and it works very fine. But i wanted to reduce nose, so I have replaced these TL072 by OPA2134, 

The noise is now perfect but the OPAs become hot..slowly buiti surely. In about 5 minutes, they become intouchable with fingers !

Here are the mods i have tried, unsuccessfuly:

- adding of 100nF caps between V+ and GND and between V- and GND for all AOPs, the nearest of the pins

- i thought the problem was about the Power supply (a symmetrical one), so i changed it from linear architecture to Switching architecture, with the good current ouput capability of course

- i have not noticed any oscillation around these AOPs

- I have checked if there was coupling capacitors everywhere between the stages

- the inputs "+" of the AOPs are linked to the GND (that is to says the middle supply because the AOPs are supplied with +/-15 V) with resistors

And nothing works, i mean the sound is very good, professionnal audio, but the AOPs are still running hots... 

But not all of them, some are really hot, others are middle hot...

And with TL072 all is ok, nothing's hot.

Does someone have already had that kind of problem?

Thanks for your help !!!


  • Stef,

    The OPA2134 can only be hot because it dissipates a lot of power inside the package.  If you use an inverting configuration, your feedback resistor is your load thus you have to calculate the RMS output power based on the magnitude of the output voltage signal and output current, and then use it together with thermal resistance of 100C/W or 150C/W for PDIP or SOIC package, respectively, to determine the temperature rise above the ambient. 

    Please review following link for discussion of op amp thermal considerations:



    If you need further assistance, please provide the circuit schematic by going to Use Rich Formatting below where you may attach the file.

  • Hello Marek,

    And thanks for your precise reply.

    I understand what you mean and i'm about to calculate these charge parameters, maybe it will help me to solve the problem.

    But there is one thing that i still don't understand: this is the difference of behavior between an OP2134 and a "simple" TL072 ? I mean if the characteristics of the components (feedback, power supply) in the environment of the AOP are the same for those 2 references, they should have the same temperature dissipation. Don't you think so ?

    Thanks again for your help,

  • Stef,

    There are some major differences between OPA2134 and TL072; for one, since OPA2134 has unity-gain bandwdth of 8MHz vs 3MHz in case of TL072, there is a significant difference in the typical quiescent current: 4mA vs 1.4mA, respectively.  Also, if you use SOIC (D) package, TL072 thermal resistance is 97C/W vs 150C/W in case of OPA2134. Therefore, if you just calculate the junction temperature rise under quiescent conditions (Iout=0), TL072 junction rise in temperature for +/-15V supplies will be:  ΔT=(30V*0.0028A)*97=8 deg C above the ambient while OPA2134 temperature will rise: ΔT=(30V*0.008A)*150=36 deg C above the ambient.  

    Of course, you need to re-calculate these for your specific load conditions which will further increase the junction temperature.

  • Dear Marek,

    Again i would like to thank you for that complete et detailed reply. And you are totaly right, your calculation corresponds exactly at what is happening on my prototype. 

    With other values of load i arrive to a temperature of 58,5°C for the "hotter" OPA2134. Clearly that is the clue for my issue !

    Best regards,