Question
What is the expected spread from chip to chip for the slope and offset parameters of this power detector? We see a spread of more than 5 dB from chipto chip when measuring power and applying a slope and Offset from datasheet or when we calibrate it on our own.
Answer
In the following I have attached a figure, which is a filtered version of one of the plots in the datasheet. This shows the part-to-part variation inoutput voltage at around 900 MHz. So what this is saying is that if you apply an input power of -10 dBm, output voltage will vary from part to partfrom about 2.35 V to about 2.6 V. In dB terms this is a variation of around 4 dB - this is approximately what your are seeing.
From this plot it is also visible, that intercept varies a lot more than slope on part-to-part basis.