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OPA211-HT: Op Amp application in very high temperature (250 C)

nader niakan
Prodigy 40 points
Part Number: OPA211-HT

Tool/software:

We intend to use this op amp (OPA211-HT)  in our pressure transducer, which needs to operate at around 250 C temperature. The parameters such as:  open loop gain, Vos, Ib are reasonable (compared to other high temp op amps in the market, like Honeywell op amp) . Has anybody used this op amp in a similar condition (high temp) ? The circuit is low power (about 20 mA), so junction temp will almost be the same as ambient. Thanks

  • 0
    TI__Mastermind 25210 points

    Hello,

    The absolute max operating temp is 210 degrees C. Going above this temperature can permanently damage the device. I don't recommend using the device at 250C. 

    Best Regards, 

    Chris Featherstone

  • 0
    Prodigy 40 points

    Thanks for the reply. We maybe able to reduce op temp to 210 C or less (using convection / heat tx heat sink). Have you used this part at 210 C ? Do you know what parameters degrade (beyond what datasheet specifies ) ?  

  • 0 in reply to nader niakan
    TI__Mastermind 25210 points

    Hi Nader, 

    I have not personally used this device. However we provide a specification table across temperature so I suspect the device has been either tested or validated at room temp and across temperature. We can only go by the specifications within the table for what varies over temperature. Was there any critical specification in particular that is a critical spec for your application? 

    Best Regards, 
    Chris Featherstone

  • 0 in reply to Chris Featherstone
    Prodigy 40 points

    Thanks Chris, as i mentioned in my original inquiry text,  parameters like open loop gain, Vos, Ib are critical in our application. The output of our thin film pressure sensor is 2mV/V (6 mv Full scale). Any significant temp variation of these parameters will be undesirable .

  • 0 in reply to nader niakan
    TI__Mastermind 25210 points

    Hi Nader, 

    Understood. We can only go off of what is in the table. The offset voltage drift is good at 2 uV/deg C but looking at the histogram it is on average is even better. 

    The input bias current is already in the 100's of nA so over temperature I don't expect a drastic change like CMOS devices where the Ib doubles every 10 degrees C due to ESD diode leakage. I would say if your application can tolerate the typical and max Ib from this device it isn't going to double every 10 deg C like that of a CMOS. 

    The Aol is actually really good at these temps. Looking at T = 210 C the typical Aol is 118 dB or 1.26 uV per every 1 volt step on the output for the 10k load. The open loop gain will reduce with heavier loads so if you can minimize the output load that will help. Additionally you can see that going from 125 to 210C the Aol is fairly well mainained for that large of a temp increase. 

    If you can minimize the temperature and the loading I think those will be key. 

    Best Regards, 

    Chris Featherstone