Question about LM5066

The collector and base of the NPN transistor MMBT3904LT1G are connected to the diode pin of the LM5066. The emitter is connected to the ground. The board was placed in a -20°C thermal chamber. We received data as 0xF0Ah while reading the local temperature register 0x8Dh. How to make the data negative in temperature. Data from the LM5066 was received correctly as 0x190h at room temperature +25.