6 years, 10 months ago.

KL46Z ADC up to 5v

Hi,

I am working with the FRDM KL46z and I would like to know if there is a way to work with the ADC conversor with Input Voltages up to 5 volts. I have seen on the reference manual, that there is a VrefH and also a VrefL but there are no real maximal or minimal values declared. In every application I have found, they take only inputs up to 3.3 volts.

Many thanks,

1 Answer

6 years, 10 months ago.

You may divide the input voltage; Tile 5K6 to and 10 K in series. Give 5V to 5K6's upper pin and connect the "joint point of 5K6 and 10K" to ADC input and connect 10K's other pin to GND.. t gives you appx. 3.3v for 5v input. But you should calibrate for precise result..

Accepted Answer

Thanks for your answer, but in fact I need to read a wider range than 0-3.3 v (from 0.7 volts to 4.8 aprox). I would take it in mind, but what I would like to know if it is possible to change the Vrefh value or not. (up to 5 volts).

posted by Alejandro Marwan Geraiges Magrini 07 Apr 2016

Ok friend, thats what I meant : you can measure 0-5v with this method. I guess, to give 5v reference to vrefh, seems risky, if you consider; Kinetis does not guarantee KL46 pins are 5v tolerant !!

posted by Özgür Kolay 07 Apr 2016

ok. Thanks again.

posted by Alejandro Marwan Geraiges Magrini 12 Apr 2016