PCT2075 temperature sensor accuracy
I read datasheet for PCT2075 temperature sensor and there are some contradicting data about accuracy for me.
accuracy ±1°C (Tamb = -25°C to +100°C)
accuracy ±2°C (Tamb = -55°C to +125°C)
figure 24 looks much better than those numbers. The accuracy looks like ±0.3°C over the whole range (nowhere near the ±2°C value).
So, how to understand this?
What is actually the accuracy?
What I care the most about is range between 0-50°C.
I have contacted NXP support and received these answers:
The accuracy of the measurement is dependent upon the definition of the environment temperature, which is affected by different factors: the printed-circuit board on which the device is mounted; the air flow contacting the device body (if the ambient air temperature and the printed-circuit board temperature are much different, then the measurement may not be stable because of the different thermal paths between the die and the environment).
The accuracy for the PCT2075 in the range from -25C to +100C is stated to be MAXIMUM within the range from -1C to +1C, so, no matter how is the design of the board or environment where the sensor is mounted, all the time should never be beyond this range.
In typical applications, with a good board design and typical environments, the real accuracy should looks something like in the Figure 24, where there are no big deviations from the real temperature.
As you can see in section 8.2 of the device datasheet, the accuracy of the measurement is more dependent upon the definition of the environment temperature other than just the device itself.
You understanding is correct, the -1C to +1C inaccuracy could be caused mostly by factors outside of device, but it is expected, as you can see in Figure 24, that the actual inaccuracy is much more closed to the +/-0.3C range. What you can see in Figure 24 are the typical values, max values can go up to +/-1C range.
These answers are to me as unclear as the datasheet is.
They say that inaccuracy of ±1°C is caused mainly by external causes, not the device itself. That device is basically inaccurate as ±0.3°C.
And then say that ±0.3°C is typical value and ±1°C is maximum value.
There's something wrong about that, isn't it?