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Max load for temperature monitor ic?

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Flyback

Well-Known Member
Hello,

I need to load the output of this temperature monitor IC with 22K. Vsuppy is 3V3.

Is this going to be OK?.... the datasheet appears to say that the maximum load is 100uA?
The datasheet seems to say that this 100uA load is actually within the Temperature monitor(?) so me loading it with an extra 22K could be bad news.


I need to load it as on some of our PCBs the temperature monitor is not fitted, and the ADC pin interprets this as overtemperature....so i want to put the pull down on the pin, so that boards without the temperature monitor get their ADC pin pulled down.

MCP9700 datasheet
https://www.electro-tech-online.com/custompdfs/2013/06/21942e.pdf
 
The datasheet seems to say that this 100uA load is actually within the Temperature monitor(?)
That's not how I read it. The spec indicates the output impedance Zo is 20Ω at the max recommended output current of 100uA. If you exceed that current by loading the output pin the measurement accuracy will be compromised because of voltage drop across Zo. The max output voltage is 1.75V, so a 22k load will give an output current of ~80uA max. You're ok providing your ADC doesn't load it additionally by >20uA.
 
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