LM5066: Negative local temperature reading issue!

NPN transistor MMBT3904LT1G collector and base connected to diode pin of lm5066. The emitter is grounded. Board placed in a thermal chamber at -20degC. While reading the local temperature register 0x8Dh, we received data as 0xF0Ah. How to convert the data to negative temp. At room temp +25, data was received properly from LM5066 as 0x190h.

Are you sure you have the correct forum? Do you want an Arduino forum perhaps?