MICS-5524 ... should I use a zener for precise input voltage

[djzman]

Hi all,

Quick question. I'm using the MICS-5524 sensor in a project. I've been working on the math to convert voltage to RS/R0 to PPM.

I knew that the input voltage mattered to the output signal, so I included it in my equations.
For example, the input voltage powered from the USB programming cable is 4.88; 5.19 from the wall wart power supply.
The output of the sensor varies proportionally.

Anyway, I was thinking I might add a zener to provide a more precise input voltage?
Does that make sense to anyone else?

Opinions valued,
Daniel

[kevinjwalters]

One thing I'd note is that wall wart PSUs are often switch mode power supplies and these tend to produce a lot of noise. I tried one to feed a cheap AMS1117 based regulator PSU and it put a lot of high frequency noise on the power (observed on an oscilloscope). Even with 5V disconnected the noise was still present indicating it's coming through GND.