MPX5700AP

The MPX5700AP is an absolute pressure sensor from NXP that measures pressure from 15 to 700 kPa relative to an internal vacuum reference, providing true absolute pressure readings. Unlike gauge sensors which reference atmospheric pressure, the absolute version references a sealed vacuum cavity on the backside of the sensing diaphragm. This makes it suitable for applications requiring pressure measurement independent of ambient atmospheric conditions, such as altimetry and manifold absolute pressure sensing. The on-chip signal conditioning and temperature compensation provide a high-level analog output directly compatible with microcontroller ADCs.

The MPX5700AP uses a silicon diaphragm with piezoresistive elements in a Wheatstone bridge configuration. The top side of the diaphragm is exposed to the measured pressure via the side port, while the backside is sealed against a vacuum reference cavity. The pressure difference between the measured media and the vacuum reference deflects the diaphragm, changing piezoresistor values and producing a bridge output voltage. On-chip amplification and temperature compensation circuitry process this signal to generate a ratiometric output from 0.2 V at minimum pressure to 4.7 V at full scale (700 kPa). Since the reference is vacuum, the output represents absolute pressure (where 0 kPa = perfect vacuum).

• Barometric altitude measurement in aviation
• Weather station barometric pressure sensing
Engine MAP sensor for ECU Vacuum system monitoring
• Industrial absolute pressure measurement