Leak rate of MPXV pressure sensor

[thierry_saive]

I face the need to evaluating the leak rate of the sensor MPXV5004GC7U.

In our application, a given amount of air is trapped at the base of a water tank but connected with a pipe to the sensor.
The air pressure gives an information about the level of water in tank.
In case of leak, the amount of air will reduce, water will finally go up in the pipe, distording the level measurement.

I found this similar question: https://community.nxp.com/message/1299877?commentID=1299877#comment-1299877 

In your answer above, you stated: "the maximum allowable leakage rate (for these devices) at our test gate is 0.182kPa/sec (with 50kPa absolute applied)."
It would definitely help to know which amount (volume or mass) of air is trapped in between the pressure test équipement and the sensor.

Could you give some values or at least rough estimation ?

Many thanks

Thierry

[reyes]

Hi Thierry,

Leakage is an unspecified and therefore not guaranteed performance characteristic of our devices. However, NXP does perform a 100% leakage test on all ported devices after assembly. The intent/extent of NXP's test capabilities is as a manufacturing quality tool/gauge to identify gross leakers (devices outside the leak test limits), NOT to quantify leakage as a cc/sec performance characteristic.

Note: the test volume is constant for all of production, so we have removed the volume variable from the quantitative leak rate equation (specifically: LR[cc/sec] = deltaP[kPa] * V[cc] / t[sec]) to achieve our qualitative gauge in kPa/sec (specifically: LR[kPa/sec] = deltaP[kPa] / t[sec]), which is the basis for our leakage test methodology.

Unfortunately, the specific leak rate value for the MPX5004 is not available, I apologize for the problems this may cause.

If you are having leakage issues in your application, I recommend you to send me detailed description of your mechanical system and leakage rate you are seen.

Regards,

Jose

NXP Semiconductors