Ultra-Low Press Click as its foundation uses the SM8436, a high precision, factory-calibrated pressure sensor for ultra-low pressure measurements ranging from 0 to 500Pa from TE Connectivity Measurement Specialties. It combines a low-pressure MEMS die with a 16 bit ASIC, utilizing DSP for multi-dimensional polynomial error correction. The calibrated pressure output data, alongside status information on the sensor integrity and unique serial number, is available via the digital data interface.

This Click board™ represents an ideal solution for lower pressure-sensing capabilities in industrial and medical markets. From HVAC and gas flow to continuous positive airway pressure (CPAP), ventilation, and patient monitoring applications, the ability to detect small pressure changes is critical. This demand requires pressure sensor to be highly accurate and provide long-term stability, which is achieved with this board.

Ultra-Low Press Click communicates with MCU using the standard I2C 2-Wire interface with a maximum clock frequency of up to 400kHz. It is fully adjustable through software registers where the digital output data is available with a word length of 16-bit. The I2C interface allows setting the SM8436 into a Sleep Mode using a specific command (Enter Sleep Mode), which confirms low consumption of typically less than 10μA. In Sleep Mode, no pressure data is acquired. To wake up the sensor from its Sleep state, the clock line SCL shall be toggled (a rising edge at SCL will wake up the device).

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the I2C communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.