The datasheet for the ad9146 is not very clear on how to change the range on the Auxiliary ADC such that the temperature range can be modified. In particular in the datasheet http://www.analog.com/media/en/technical-documentation/data-sheets/AD9146.PDF, p26 of 56, we see that the register 0x48 corresponds to a Die Temperature Range register, but there is no detail in the spec sheet on how this actually works. Could someone please enlighten me?
In the Temperature Sensor section of the datasheet (page 44 of Rev A) it mentions that the die temperature range control register (Register 0x48) should be set to 0x02. This value is the recommended setting for the optimal temperature sensor performance and to coincide with the equation listed in the datasheet. Changing these controls will effect the accuracy of the equation so we do not recommend this be set to anything different - just simply listing in the register map what the controls are in that register that you are setting to those values.