MPX53DP voltage output

[jordan123]

According to the datasheet for the MPX53DP differential pressure sensor, the output voltage should be in the range of 20-80mV, proportional to the differential pressure.

I have set it up with a 3.3v power supply and was expecting to need an amplifying circuit but at a differential pressure of 0 (both nozzles are open), the output voltage is 1.75V. However, when I apply pressure, the voltage rises as expected in the datasheet.

So my question is this: How do I have an offset of 1.75V when it should be 0.02V?

Thank you in advance for your help

Jordan

[TomasVaverka · Accepted solution]

Hi Jordan,

I believe you are measuring the voltage on either +Vout or -Vout output with respect to GND. However, you should measure the differential voltage between +Vout or -Vout. At the maximum differential pressure of 50kPa, the differential output voltage between +Vout or -Vout should be around 60mV.

I hope it helps. If I misunderstood your question or if you have further questions, please let me know.

Best regards,

Tomas 

[naitali]

. I am working on a project to detect change in breathing patterns and I am using an MPX53D pressure sensor.

Using a cool hair dryer to reproduce the breathing exercise, I apply different pressures on the MPX53D and when I measure the difference output voltage using Fluke 115 Multimeter between (Vout +) and (Vout -). 

The voltage difference does not exceed 25 mV and the MPX53D data sheet indicates Full scale span  is  45mV <Vfss< 90 mV.

Please, any help would be appreciated.

[jordan123]

Thank you so much Tomas - It seems so simple once you put it like that.

I will have to use a differential op-amp then :smileyhappy: