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Tool/software:
Hi TI
I'm working with the ADS7828-Q1 ADC and utilising the internal 2.5V reference provided on the REF OUT pin.
I have a thermistor that I am measuring the resistance of, to derive PCB temperature. I have the thermistor as the bottom half of a typical potential divider, the top resistor is a regular 10k, this potential divider is supplied from the REF OUT pin.
I want to verify that I do not draw too much current from the REF OUT pin, however, I couldn't find specific information in the datasheet regarding the maximum allowable current that can be drawn from the REF OUT pin without degrading the reference accuracy.
The datasheet specifies a load regulation of 500 µV/µA, but it doesn't mention a hard limit on the maximum current draw.
What is the recommended maximum current I can safely draw from the REF OUT pin without compromising the reference stability or ADC performance?
Thanks in advance for your help!
Best regards,
Charles
Hi Charles,
We do not usually specify a MAX current limit on the internal reference due mainly to the potential impact it would have on the conversion process. If you wish to use the internal reference of the ADS7828-Q1 to drive your thermistor, it would be best to put it through an external buffer first. The TLV9001-Q1 is a potential option for you.
Hi Tom
Thank you for your reply and your answer. We will look at adding a external buffer on the next respin.
Regards,
Charles