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Calculating chip temperature from register value on VN9D30Q100F

Phydiux
Associate II

Reading through the datasheet, I'm unable to find information about the VN9D30Q100F's ADC9SR value. the address 0x31h returns a 10-bit ADC value, but there's no information on a conversion factor - I have a value with no idea what it means. 10-bit ADC, coming up with stuff like 0x16D, that comes out to 1.187v. I can't find anything useful about this in the datasheet, though, so I don't know how that converts over to a temperature value. What am I missing in the datasheet that tells me this?

1 REPLY 1
Phydiux
Associate II

After digging through data sheets for a while, I stumbled across one single line in the datasheet for the VN9D5D20F (the 4-channel version of the VN9D30Q100F) that shows a conversion for the case temperature:

TCASE (typ.) = 401.8 °C -1.009 * ADC9SR[13:4] 

The ADC value I'm getting on my VN9D30Q100F, when plugged into that, seems to mostly make sense (in the example that I originally posted, it comes out to 33.5C.) Is this correct? I'm rolling with it for now, but it'd be real great if ST could confirm and update their datasheets with information about how to use this chip.

Maybe this follow-up will help some internet stranger in the future when they end up using this chip.