Technical specs KITLOPRESSMPX12 evaluation board?

[njiruk]

Hi, Just having bought a Freescale MPX12GP pressure sensor, I'm looking for an amplifier to connect it to my DAC-interface. I suppose the KITLOPRESSMPX12 evaluation board would be a very suitable option, but as there are no technical details nor datasheet available I wanted to make sure that this circuit outputs an analog amplified voltage around 5V? I'm also wondering what the supply voltage would be. Thanks!

[TomasVaverka]

Hi Njiruk,

Unfortunately, I do not have any documentation for the KITLOPRESSMPX12 either.

The MPX12GP is of the differential output type with output voltage in the mV range and to read the output with any useful resolution, it is necessary to increase the gain of the MPX10GP using a differential amplifier. You can build one yourself, but I would strongly recommend buying a single chip version of the most generally useful variety, called an "instrumentation amplifier". For instance, the INA122 instrumentation amplifier is inexpensive, widely available, suitable for operation from a single +5V supply and the only thing you need to do to set the gain is choose a gain resistor.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.

[njiruk]

Thanks.

By observing an image of the KITLOPRESSMPX12 circuit, I figured out that it is based on the LM234A quad-opamp (although, I don't know the resistor values).

I also found out about the general instrumentation amplifier option indeed. I think I'd opt for the INA125P, which should have better precision as it is quad-amp based as well.

Just out of curiosity: would it be possible that a sensor-specific instrumentation amplifier performs better in some way? Otherwise, I obviously go for the INA-approach, easy, cheap and even more compact!

Best regards,

Qrain