STMicroelectronics — LPS28DFW Pressure Sensor

The LPS28DFW from STMicroelectronics is a piezo-resistive absolute pressure sensor which offers a selectable dual full-scale mode, enabling its use either under water, or to measure atmospheric pressure.

In Mode 1, the LPS28DFW’s full-scale measurement range is from 260 hPa to 1,260 hPa, for use in air. In Mode 2 for use under water to a depth of up to 30 m, the full-scale range is 260 hPa to 4,060 hPa. This dual altimeter and depth meter capability makes the device ideal for use in personal and consumer devices such as sport watches.

The digital LPS28DFW, which measures pressure at 24-bit resolution, is notable for its low power consumption and low pressure-sensor noise of 0.32 Pa in Mode 1. The absolute pressure measurement accuracy is ±0.5 hPa.

The sensor is supplied in a ceramic LGA package, and has a cylindrical metal lid which allows for easy assembly with O-rings in the end product. The package is holed to allow external pressure to reach the sensing element. Gel inside the IC protects the electrical components from water. The metal cap may be grounded electrically to better withstand ESD strikes, or left floating to improve EMI performance.

A built-in temperature sensor measures ambient temperature to an accuracy of ±1.5°C. The device implements temperature compensation automatically, achieving absolute accuracy of pressure measurement of ±0.5 hPa at pressures between 860 hPa and 1,160 hPa. The output data rate for pressure measurements is configurable between 1 Hz and 200 Hz.

The compact device comprises a MEMS sensing element and an IC interface which communicates through an I2C or MIPI I3C® interface from the sensing element to the application. The sensing element, which detects absolute pressure, consists of a suspended membrane manufactured using a dedicated process developed by ST.