AD8314: Temperature compensating the AD8314

Document created by analog-archivist Employee on Feb 23, 2016
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Hello, for our exact measurements I need to know the detailed
temperature drift of the detector AD8314 at 2.5GHz (in our application
2.3GHz). Can you send me the V_UP vs. Input Amplitude for T=-30
to  85 centigrade (as shown in Figure6 of the datasheet) in a
more exact format (maybe as a table).  The range of values from
-20 dBV to -40 dBV is of interest for us.


The problem with temperature compensation of the AD8314 is that every device
has a different amount of temperature drift (the datasheet just shows a typical
device). Even over the restricted range there will still be significant device
to device variation.

We do not have the specific data you request and even if a few sample devices
were tested, we could not guarantee drift over all devices as this parameter is
not production tested. However, to give you an idea, the drift for the AD8314
will look a lot like the plots of drift in the AD8315 datasheet (TPC
7,8,10,11). As you can see the spread is quite large.

I'm attaching notes for compensating the AD8313. In the case of the AD8313, the
drift of the part is higher but it is more consistent. However, even with using
this technique, I believe that you can at best get +/-1 dB over temperature.
This scheme will only work for the AD8314 if you were to measure the drift of
each individual device and separately compensate each one.

You may be able to achieve this by using a similar technique to that given in
the note and using a digital pot to adjust the values of R1 and R2 while
performing a single point temperature calibration. Further enhancements are
possible by calibrating at two or more temperatures.