Is there an internal precise reference voltage for the ADC measurements?

Tobias Klocke · ‎2017-07-28

Posted on July 28, 2017 at 10:46

Hello Community,

I am measuring several voltages and I would like to have a precise reference to be able to calculate the best physical value without using any external reference.

The ADC uses for the internal conversation VDD, which is supplied by an external voltage regulator. Actually these regulators have a high tolerance, so that I cannot be sure to have 5 V.

I could use an external IC to generate a precise 1.2V or 2.5V reference and read this with the ADC.

Actually I was asking myself if I cannot get rid of this external refernce IC and use any precise internal voltage?!

Does somebody know if there is any internal voltage (like the internal 1.2V for example) which I can read as the reference voltage? Is it precise enough? Is it maybe already availabe by the uC Architecture to be directly read?

Thanks for your answers!

Regards,

Tobias

#high-precision #adc #reference #measure #voltage

Erwan YVIN · ‎2017-08-09

Posted on August 09, 2017 at 15:52

Hello Tobias,

for SPC56 MCUs , the reference voltage is 3.3 V or 5V.

for 1.2V , (VDD_LV) there is an interesting chapter (SPC56D Example)

you should use 12 bit ADC conversion on a precision channel.

(cf ADC Chapter)

Best regards

Erwan