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INA103 has a temperature of 41°C

Alexander Bucher
Prodigy 90 points
Other Parts Discussed in Thread: INA103, INA101, INA111, INA114, INA115, INA116, INA118, INA121, INA128, INA129, INA163, INA217

 

Hi

I use an INA103 in the same configuration as shown in figure 1 (page 9) in the datasheet. The differential voltage on the inputs is 0 mV to 1000 mV. +/-15 V supply is used an the Gain is 3. If I turn the power on, the INA103 is getting warm and when I add an 1 V input voltage I can measure 41°C on the package. Even if I disconnect everything from the output, the INA103 is still hand-hot.

Is it normal that this device is getting so hot?

Best regards

Alex

  • 0
    TI__Guru**** 189399 points

    Hi, Alexander,

    This device is supported by our Precision Amplifier team. I am moving your thread to their forum.

    -d2

  • 0
    TI__Mastermind 25805 points

    Hello Alex,

    I am working on this and will get back with you shortly.

     

  • 0
    TI__Mastermind 25805 points

    Hello Alex,

    Yes, this is normal behavior.

    The INA103 has a quiescent current of 9mA (typ) and 12.5mA (maximum).  With the supply connected to 30V, this corresponds to 270mW and 375mW, respectively.  The thermal impedance is 100C/W (typ).  Therefore you can expect from 27C (typ) to 37.5C (max) temperature rise under quiescent conditions.  41C (which is ~16C above ambient) is actually below the expected range.

     

  • 0 in reply to Pete%20Semig
    Prodigy 90 points

     

    Hello Pete

    Thank you for your detailed answer.

    The operating temperature range of the INA103 is from 0°C to 70°C. If I have to expect that the temperature rise is up to 37.5C, hence the ambient temperature should be less than 32.5C. Is there a variation of the INA103 which is specified for ambient temperatures up to 50°C?

    Kind Regards

    Alex

  • 0 in reply to Alexander Bucher
    TI__Mastermind 25805 points

    Hello Alex,

    The INA103 is a unique topology that is well-suited for applications that are typically at room temperature.  So the unfortunate direct answer to your question is no, we don't have a higher temperature grade version of this particular device.

    A number of our more traditional instrumentation amplifiers, however, do come in higher temperature grades.  From what I understand of your application, your supply voltage is 30V (+/-15V) and the gain is 3.  Your selection of the INA103 indicates to me that you're interested in a 3-op-amp topology.  With that in mind, here is a list of instrumentation amplifiers that meet the aforementioned criteria and are rated for the industrial temperature range (-40C to 85C):

    INA101
    INA111
    INA114
    INA115
    INA116
    INA118
    INA121
    INA128
    INA129
    INA163
    INA217

    I hope this helps. 

  • 0 in reply to Pete%20Semig
    Guru 21975 points

    Alex,

    The 70'C rating on the INA103 is an ambient temperature rating. The temperature of the actual device is allowed to rise above 70'C.

    Regards, Bruce.

  • 0 in reply to Bruce Trump
    Prodigy 90 points

     

    Thanks Pete and Bruce. 70°C is more than I need but I will also have a look on the other Amplifiers.

    Regards

    Alex