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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
Hi, Alexander,
This device is supported by our Precision Amplifier team. I am moving your thread to their forum.
-d2
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.
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
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.
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.
Thanks Pete and Bruce. 70°C is more than I need but I will also have a look on the other Amplifiers.
Regards
Alex