Here is the DTH,
On the preference page of the Environment Sensor, you can enable the analog input. Then, specify TempProbe as handler.
The calculation on the following line may need to be adjusted. You may not need the -250 on the following formula.
float temp = ((((((zigbee.convertHexToInt(adc)*state.lastVdd)/0x1FFF)+0.025)*2) -1.25)/0.005) -250.0
AD8495 can be fitted by configurable reference voltage. I found a hard lesson that some vendor may have different refernce value. Once you got the board, we can try some experiment to find out.
You can power AD8495 from 5V or 3.3v. If you power it from 5V you may need to have voltage divider. The code currently assume that you will be powering from voltage divider. The reason for voltage divider is that using 5V, you can measure higher temperature. But, the MCU is can only measure up to 3.3V. The voltage divider will divide the output voltage to make it lower. The code above use 1/2 voltage divider. If you go this route, the ideal resistor value is 10k.
If you are fine with 3.3v, you can connect the output of AD8495 straight to the AI. Then, the code to calculate the temperature is
float temp = ((((((zigbee.convertHexToInt(adc)*state.lastVdd)/0x1FFF)+0.025)) -1.25)/0.005) -250.0
You just need not to multiple the voltage calculation by 2. Using 3.3V as power to AD8495 will simplify the wiring. It is just support less temperature range. Based on what you mentioned, you are not trying to measure extreme heat, I do not see that you need higher voltage. AD8495 can be powered up to ~18v for higher temperature support.