STMicroelectronics’ LPS33W water-resistant MEMS pressure sensor combines chemical compatibility, stability, and accuracy for use in a wide range of applications such as fitness trackers and other wearables, vacuum cleaners, and general-purpose industrial sensing. Protected by a viscous potting gel inside the cylindrical metal package, the IPx8-rated component withstands salt water, chlorine, bromine, detergents such as hand soap and shampoo, e-liquids, and light industrial chemicals such as n-pentane. The package lid provides high corrosion resistance, and the cylindrical form factor is easy to use with O-rings in applications that require a sealed enclosure.
Properties of ST’s proprietary gel formula, together with the sensor’s built-in signal-conditioning ASIC, ensure 0.008hPa RMS pressure noise. Susceptibility to reflow-soldering stress during assembly drifts less than ±2hPa and recovers normal accuracy in 72 hours, allegedly more than twice the speed of other sensors. Temperature compensation keeps accuracy within ±3hPa over the operating range from 0°C to +65°C.
The LPS33W operates at 15 µA in high-performance mode, with a 3 µA low-power mode and 1 µA power-down. A 128-bit FIFO stores up to 40 slots of 32-bit pressure and temperature data, helping save extra power by minimizing intervention from the host microcontroller. A low-pass filter and I2C and SPI digital interfaces are also built-in.
The LPS33W is in mass production now, in a 3.3-mm diameter x 2.9 mm cylindrical metal case, priced from $3.60 each/1,000. For deeper revelations, take a look at the LPS33W datasheet.