Convert 5V analog signal level to 3.3V for nRF52832 ADC

[chianglin]

Hi,

I am using nRF52832's ADC function to do my project, and I have an analog signal level problem.

I am try to connect MPX5100 sensor to nRF52832's ADC port, but the output of MPX5100 is 5V and output current is only 0.1mAdc. Please fine following attach image.

May be the output current is too small, so I can not use "voltage divider resistor" to do this job.

Would you please give me a suggestion "level shifter IC“, and the IC is simple and cheap.

Best Regards,

Chianglin

[ketiljo]

You can use a voltage divider with large resistors and a capacitor at the AIN pin. The capacitor will be charged (slowly) by the voltage divider and when the ADC conversion takes place, the charge in the capacitor makes sure the large resistors don't influence the conversion. See more here: https://devzone.nordicsemi.com/b/blog/posts/measuring-lithium-battery-voltage-with-nrf52