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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.
I’ve read some tutorials like https://www.kynix.com/components/MMBT3904LT1G-Bipolar-BJT-Transistor-CAD-Models-Datasheet-Features.html, but I still have no idea.
Thanks.

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See the LM5066 datasheet.

In reply to LM5066: Negative local temperature reading issue !

The values read do not tell you temperature without some math. Read the datasheet where it writes:
“Conversion from direct format to real-world dimensions of current, voltage, power, and temperature is accomplished by determining appropriate coefficients as described in section 7.2.1 of the PMBus Power System
Management Protocol Specification 1.1 (Part II). According to this specification, the host system converts the values received into a reading of volts, amperes, watts, or other units using the following relationship:”

Sorry no, I do not have the codes to do this for you. There may be examples on the web.

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