MLX90821 Relative Pressure Sensors Melexis MLX90821 Relative Pressure Sensors are factory-calibrated relative pressure sensors that deliver a ratiometric analog output or a digital signal using the SENT protocol. MLX90821 features a MEMS sensor that enables reliable and accurate measurement of low pressures of a few tenths of millibars. These Melexis relative pressure sensors include an optimized architecture and high-density CMOS technology. These design features provide leading automotive electromagnetic compatibility (EMC) performance. The digital-signal-processor architecture uses a 16-bit microcontroller to provide high initial accuracy of pressure and optional external NTC temperature.