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OPA2192: GBW and Slew Rate - minimum values and temperature coeffiecient

Elder Costa17
Expert 2825 points
Part Number: OPA2192
Other Parts Discussed in Thread: OPA2140

The data sheet states only the typical value for GBW, 10MHz along the whole voltage range.

I have determined through simulations that the design is fairly sensitive to variations in this parameter. Knowing the minimum value will help me to determine if the calibration range of the circuit is OK. Moreover, calibration is sensitive to GBW variation so it would help knowing how much it varies with temperature, for a delta T of 30°C, from 10 to 40°C ambient temperature.

Regarding Slew Rate, I need to know the minimum to make sure I have enough margin to guarantee the design will work with the input signal I drive it with.

FWIW currently we are using the OPA2140 in a similar design. It works OK but the circuit requires some warm-up time before it is available. The OPA2140 replaced another part from AD that had a higher variability and caused calibration issues. The replacement apparently fixed the calibration issue but I would like to avoid the warm-up in this new design if I can. I need to reduce the supply voltage to reduce power consumption. Using OPA2192 will allow me to reduce it further as it is RRIO.

  • 0
    TI__Guru* 93105 points

    Hello Elder,

    I am only able to provide estimations of the OPA2192 slew rate and GBW spreads due to process variation and over temperature because these parameters are specified with "typical" values in the datasheet. Therefore, TI provides no assurances about the information that follows.

    The estimated variation in these two ac parameters due to process variances is approximately +/- 25 % about the typical value. Thus, for the slewing rate the range would be from 15 V/us to 25 V/us, and for the GBW from 7.5 MHz to 12.5 MHz. The distributions should be normal when many production lots are considered.  

    The temperature coefficient of these parameters should be low in both cases because their circuit bias sources are temperature compensated. The change in the slew rate and GBW is estimated to be less than 1 % over the narrow temperature range you mention.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • 0 in reply to Thomas Kuehl
    Expert 2825 points
    Hello Thomas,

    That is helpful. It at least provides a ballpark I may work with.

    Thank you very much.
  • 0 in reply to Thomas Kuehl
    Expert 2825 points
    I have a follow-up question: how well the two amplifiers match, gain wise, GBW wise and TC wise?
  • 0 in reply to Elder Costa17
    TI__Guru* 93105 points

    Hello Elder,

    Usually, the ac parameter performances for the different amplifier sections of dual and quad operational amplifiers are very close. That is because each amplifier has a nearly identical layout on the silicon die to the other(s), and they are processed simultaneously under identical conditions. They should track well with temperature due to their very close physical and electrical similarities.

    A few years ago one of our applications engineers - Bruce Trump, put together a nice little presentation about op amp questions. There is a section where the subject of matching dc and ac parameters for duals and quads is discussed. That may shed a little more light on your question:

    Regards, Thomas

    Precision Amplifiers Applications Engineering