Accidentally put pinout on the board backwards so P1 is facing down (towards my vaccuum) and we were planning on using the MPX2100D. Can I save myself redesigning the board by just using the MPX2100A?
The absolute pressure (MPX2100A) refers to the absolute value of the force per-unit-area exerted on a surface. Therefore the absolute pressure is the difference between the pressure at a given point and the absolute zero of pressure or a perfect vacuum.
Pressure is applied on Port P1 of the sensor while the Port P2 of the sensor is a vacuum sealed reference.
In the other hand, the differential pressure (MPX2100D) is simply the measurement of one unknown pressure with reference to another unknown pressure. The pressure measured is the difference between the two unknown pressures.
The difference in pressure between two points is measured where pressure is applied to both sides (Port P1 and Port P2) of sensor.
I recommend to be aware about the information mentioned above, in order to determine if you can save the design.
In order to get more detailed information about the Mounting Techniques, Lead Forming, and Testing of the MPX Series Pressure Sensors, please refer to the following application note:
I hope this information will be useful for you.
If I misunderstood your question, feel free to let me know. I will be glad to help.
Have a great day.