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OPA377-Q1: OPA377

Part Number: OPA377-Q1
Other Parts Discussed in Thread: OPA377

Hi Team,

As i am working on amplifier OPA377QDBVRQ1  and require some input 

1. output voltage V/s  output current graph at 85degC for 0 to 3.3V

In datasheet it provide -40 to 150 degC

  • Hi Gaurav,

    I would take figure 12 and do a linear interpolation. Also keep in mind that figure 12 shows typical behaviour only. It doesn't say anything about wafer to wafer and lot to lot tolerances.

    Kai

  • Hi Gaurav,

    Per your inquiry, I am doing a linear interpolation as suggested by Kai. 

    With 3.3V, if the load is 10kΩ, the Vout voltage swing will be up to 3.3V - 40mV = 3.26Vdc range at 85C based on the datasheet below (this is not worst case scenario per the test condition). If the load current is near approx. 10kΩ, the output voltage swing 3.26V is the figure at 85C (current: 5.5V/10kΩ=0.55mA).

    From the Figure 12 above, if the 2.75V is applied, at 10mA load, the output swing is up to approx. 2.5Vdc at 85C. 

    Assumed the single supply voltage is 3.3Vdc, the output swing is likely up to 2.5Vdc + (3.3-2.5V)= ~3.3V, which I will pick 3.26V from the above at 85C. 

    Q: output voltage V/s  output current graph at 85degC for 0 to 3.3V

    As in every published datasheet, the above estimation is based on an extrapolation. For 10mA load, if supply voltage rail of 2.75Vdc will generate 2.5V Vout swing, 3.3Vdc will estimated to generate Vout swing of 3V.  The output voltage swing is a function of output load current in a given supply voltage up to 85C. 

    In addition, I would place some additional margin (e.g.  50-100mV margin) to the figure above, say the output voltage swing from rail should be approx. 2.90V to 3.0V range at 85C at 10mA. 

    If you have additional questions, please let me know. 

    Best,

    Raymond 

  • HI Raymond,

    Can you provide me the graph as i mention ?

  • Hi Gaurav,

    What is the application's max. output current or load in OPA377? Please clarify. 

    I will ask the validation team to get the raw data and provide the extrapolation, but it may take a couple days to get the data.  I will post the result,  if the raw data is available.

    If OPA377 application is driving a load at approx. 10kΩ, the answer to you inquiry is shown below --> output voltage vs. output current with Vs from 0 to 3.3V at 85degC.

    Best,

    Raymond

  • Hi Raymond,

    As per application Max. output current in range of 15mA -25mA.

    Thanks,

    Gaurav Ingle.

  • Hi Gaurav,

    I am unable to find the raw data per OPA377 plot, so the generated data is digitized extrapolation of the above plot for 0 < Vs < 3.3Vdc at 85C. 

    As per application Max. output current in range of 15mA -25mA, I do not see that OPA377 is able to support source current at 25mA at Ta = 85C.

    Here is how I did the data extrapolations:

    1. Digitized the Figure 12 with WebPlotDigitizer tool.

    2. Performed a curve fit from the obtained digitized points for -40C, +25C and +125C.

    3. Duplicate Figure 12 after obtaining the curve fit equation y(x)  = (a+cx)/(1 + bx +dx^2) or polynomial.equation. 

    4. Estimate/calculate the data points at 85C in Voltage vs. Current, and curve fit with the similar curve equation found above.

    5. Shift all curves upward for Vs=3.3Vdc (Figure 12 is presented for Vs = +/- 2.75Vdc). 

    If you have additional questions, please let me know. 

    Best,

    Raymond