Pressure sensor selection

[jeffrickard]

Hello,

I'd like help selection an air pressure sensor chip for a new product. I'll give a summary of our requirements here:

- Size: Not critical, but we're looking for a PCB-mount chip to measure the air pressure at the chip.

- Pressure range: Normal ambient pressures at normal ground altitudes.

- Operating temperature range: Preferably at least 0-60 Celsius.

- Interface: For design simplicity, an I2C or SPI interface would be highly desirable.

- Sample rate: We need accurate data at about 10Hz, so allowing for noise I expect we need about 100Hz or higher.

- Voltage: Preferably 3.3V, but we can probably design around 1.8V or 5V.

- Power: Fairly important, preferably in the Milliampere range, but we can make allowances for more power if necessary.

- Cost: Around a couple of dollars per chip.

- Accuracy: This is critical. We do not need absolute accuracy or temperature stability, but we need to accurately measure pressure differences over a period of seconds with a resolution of 1Pa (0.001 kPa). We're well aware that this will be beyond the specifications of any chip we choose, but I believe that over a period of seconds with no need for temperature stability or stability over longer periods of time, and appropriately filtering the data to remove noise, we should be able to achieve a 1Pa resolution for measuring pressure difference at about a 10Hz rate.

[TomasVaverka]

Hello Jeff,

Thank you for your interest in NXP pressure sensors.

Based on your requirements, I would recommend considering the MPL3115A2.

- Size: 3 x 5 x 1.25mm 8-pin LGA package

- Calibrated pressure range: 50kPa to 110kPa absolute pressure

- Operating temperature range: −40°C to +85°C

- Interface: I2C only

- Sample rate: Depending on OS[2:0] bits, more in Table 46 of MPL3115 datasheet

- Voltage: 3.3V is OK (1.95V – 3.6V)

- Power: Depending on OS[2:0] bits, more in Table 6 of MPL3115 datasheet, the max current during acquisition and conversion is 2mA

- Cost: 1K @ US$1.69

- Accuracy/Resolution: Depending on OS[2:0] bits, theoretically 1.5Pa @ max OS[2:0] = 0b111, a quick test on my desk:

To evaluate the MPL3115A2, we can offer a complete demo kit, an Arduino/Freedom compatible shield board or just a breakout board - MPL3115A2 Pressure Sensor Development Boards|NXP.

If you have any further questions, please let me know. 

Best regards,

Tomas

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

[jeffrickard]

Hi Tomas,

Thanks for your help. I'll order a couple, attach it to our current

prototype, and see how it performs. Based on the datasheet it looks like

the accuracy may only just manage to fit our requirements - a bit faster

and a bit more accurate would be better - but there's a good chance that in

real-world conditions we'll have more problems with accuracy due to the

housing (porting, vibration) than due to the sensor. We'll soon find out!

Regards,

Jeff

On 19 September 2016 at 12:20, TomasVaverka <admin@community.freescale.com>