Pressure Sensor Selection and Error Reduction (auto-zero)

[andrewsauter]

Hello,

We are looking for a pressure sensor for a medical device with EAU 100s starting in 2024. Please see further details and questions and correct or clarify as you see fit. Thank you.

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Questions:

Is this the correct part?

Will I hit my accuracy specs?

Any product roadmap info you can offer?

Any sourcing suggestions for our immediate development use?

Pressure Sensor Mechanicals:

one barbed output, PCB mounted

Pressure Sensor Use Case:

-16kPa +/- ~2.5%

-2.5kPa +/- ~0.8kPa

operating temperature 15~25C

disposable device used for 10 days

Tentative Candidate:

MPXV5050DP and we feed our pressure into the negative port to create a positive reading

We perform auto-zero every 24h when the pressure is ambient on both ports for a few minutes

EAU:

100s per year

I noticed factor lead-time just increased from 40 to 80 weeks

looks like we can buy stock from the secondary market for development needs 

[andrewsauter]

We are measuring the pressure on an open would, but no contact with bodily fluids. Does that mean we do not require an invasive rated pressure sensor?

[diazmarin09]

Hello Andrew,

I hope everything is great for you.

Besides the MPXV5050DP device (is a great option) and based on your requirements, I would like to recommend the series below:

MPX230xDT1 – Differential, Compensated Pressure Sensor (0 to 40kPa)

The MPX230xDT1 offers a cost-effective, high-volume miniature pressure sensor package targeting medical applications, including the Invasive blood pressure monitoring.

As mentioned, this pressure sensor can be used with confidence in applications such as invasive blood pressure monitoring. It can be sterilized using ethylene oxide. The portions of the pressure sensor that are required to be biomedically approved are the rigid housing and the gel coating.

For Non-Invasive blood pressure monitoring I would like to recommend the series below:

MPXx2053 - Differential and Gauge Compensated Pressure Sensor (0 to 50kPa)

This pressure sensor supports applications such as pump/motor control, robotics, level detectors, pressure switching, medical diagnostics, and blood pressure measurement.

Please note that P1 must be greater than P2. If negative pressure is applied to this device, the internal structure of the sensor might get degraded causing permanent damage.

I hope this information will be useful for you.

Regards,

David

[andrewsauter]

Thanks for the reply.

MPX230xDT1- This apparently only measures pressures over ambient, we are measuring pressures below ambient. This unit is differential in its electrical output, not in its pressure inputs.

MPXV2053DP- Is this the same part as the MPXV5050DP but without an internal amplifier? Please let me know how much cheaper is this part than MPXV5050DP typically, because currently prices are distorted by availability. I am looking to specify the amplifier stage so that we can compare the relative cost & performance of MPXV2053DP+amp vs MPXV5050DP, please send any relevant NXP app notes, many of the app note links in the datasheet are broken.

[diazmarin09]

Hello Andrew,

Thank you for using the NXP communities.

1. Exactly, the MPXV2053DP device is differential, which means that the sensor gives you a differential output in the range of millivolts (output is already internally temperature compensated), you need to externally add the amplification circuit before sending the sensor’s output signal to the MCU’s ADC.

I would like to recommend the document below for further information:

Interfacing Semiconductor Pressure Sensors to Microcomputers

2. You are correct. In general, our pressure sensors were designed and are warranted for use in clean dry air only. Therefore, if you pressure sensor does not have direct contact with fluids, you do not require an invasive pressure sensor.

Regards,

David