Run DC analysis with temperature as sweeping parameter.
Using calculator select VS of bandgap voltage. Then select DERIV Special function of calculator and click plot. You will get TC. If you prefer PPM multiply it by 1000000.
where to find calculator?
what is the PPM 's definition? if Temp coefficient is 50ppm/C. what is this?
Fom said:
Run DC analysis with temperature as sweeping parameter.
Using calculator select VS of bandgap voltage. Then select DERIV Special function of calculator and click plot. You will get TC. If you prefer PPM multiply it by 1000000.
It depends on your interpretation. But if I want a numerical value, this is what I use.
Given the operating temperature range and the nominal operating temperature,
TC(V/K) = (Vbg(max)-Vbg(min))/(Tmax-Tmin)
TC(ppm/K) = 10^6*(Vbg(max)-Vbg(min))/((Tmax-Tmin)*Vbg(nom))
* Note that I left out the sign, which you will have to determine from the curves.
The plotted derivative function is \[\ \frac{\partial (voltage) }{\partial (temperature) } \] in units of \[\ \frac{V}{°C}\ \]. Divide this function by your nominal Vref - e.g. 1.22V @ 25°C - and multiply it by 1.000.000 (ppm = part per million), so you get \[\ \frac{V}{°C} \times \frac{10^6}{Vref[V]) } = \ \frac{ppm}{°C}\].
The relative temperature dependence of your ref. voltage (in \[\ \frac{ppm}{°C}\]) will change over the temperature range. Which value you should take depends on your specification needs: you could specify several \[\ \frac{ppm}{°C}\] values for their corresponding temperature points, or you could specify min. & max values for a specified temperature range, or a mean value for such a range ± its max. deviations, e.g. for the application temperature range.
See also company bandGap dataSheets how they specify their values.