Smoke detector interfacing with FS32K146HAT0MLLT

[ultra12]

I am using MQ-2 smoke detector in my design.The sensor is working at 5V supply.This sensor has both analog and digital outputs.

I am using analog output in my design.The microcontroller used is FS32K146HAT0MLLT from NXP.The controller is also working at 5V.

The analog output varies from 0V to 5V so I did not use any voltage scaling circuit between sensor and microcontroller.

A LPF of cut off frequency 1.6Khz(arbitrarily chosen) is kept at the output of sensor.

May I know this circuit is fine or do I need to take care any other things.

In the datasheet I can see a current limit resistor(RL).Is that necessary. How do I design that resistor.

[davidtosenovjan · Accepted solution]

I would attach such guide for selecting components external to ADC. Although written for different device, used SAR ADC is very similar module, they may be minor differences in specified values.

Hope it helps