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Opamp performance across ambient temperature

Zhou Fang67
Expert 4250 points
Other Parts Discussed in Thread: OPA2171

Hi,

Normally, in OPAMP datasheet, it is said that the device can operate across -45~85/125 in ambient temperature or free-air temperature.

1. Where the temperature is measured? How far between testing node and device?

2. What it the loading current when doing temperature performance evaluation?  e.g. in OPA2171, the Rload = 10k Ohm across Ta = -40 to +125. Does it mean, the load resistor is 10K Ohm when the testing is performed across -40 to +125?

Thanks a lot.

Zhou

  • 0
    TI__Guru* 93105 points

    Hello Zhou,

    When a specific temperature, or temperature range, is specified in the op amp Electrical Characteristics table it usually specifies how it is referenced. In the case of the OPA2171, the Electrical Characteristics table lists TA = 25°C, or  it referenced to an ambient temperature of 25°C. During product characterization the op amp is placed in a temperature-controlled oven where the air temperature is maintained at the specified reference temperature. Sometimes case temperature (Tc) is specified and when specified as such the case is forced by some means to that temperature. 

    The OPA2171 Electrical Characteristics table specifies a RLOAD = 10 kΩ connected to VS / 2, unless otherwise noted. The load current will depend on the particular electrical test. If voltage offset is being tested the current through the 10 kΩ load will be very close to zero. On the other hand an output swing test will produce an output current dictated by Ohms law, Iout = Vout /10 kΩ. If the test specifies a 10 kΩ load over a wide temperature such as -40 to +125 C, then indeed the load is in place.

    Regards, Thomas

    PA - Linear Applications Engineering