Hi Expert,
My customer is checking the datasheet for OPA1654 and OPA1664.
Regarding the figure of Voltage noise below,
(1) Regarding Figure1
It is shown the data at 25C.
Do you have any data at 50C?
If no, how will the voltage noise characteristic at high temp?
(2) Regarding Figure3
It is shown the data at 25C.
Do you have any data at 50C?
If no, how will the voltage noise characteristic at high temp?
Thanks
Muk
Regarding Fig 1, a flicker (low frequency) noise is not a function of temperature while the white (broadband) noise may at most change as a square-root function of absolute temperature - thus for temperature change from 25C (298K) to 50C (323K), the broadband noise could increase at most by about 4%; sq-rt(323/298).
As far as Fig 3 goes, the equation shows the variation with temperature: 
First term, en^2 refers to Fig 1 (~4%)
In a second term, in=(2*q*IB)^.5 (negligible change with temp for OPA1654)
Third term, 4KTRs, proportional to absolute temp (~4%)
In total voltage noise shown in Fig 3, should not increase at 50 deg C temp by more than 6%.
