MLX91804 comes in a robust 14-pin DFN type leadless package, this product has a 60% smaller footprint and draws three times lower sleep mode current than any competing TPMS IC on the market, the company asserts. It incorporates a microcontroller and MEMS-based pressure sensing element, as well as energy-efficient 315/433 MHz wireless transmitter (supporting data rates up to 150 kbits/sec) and 125 kHz receiver for communication with the vehicle’s relevant electronic control unit (ECU). A 16 kB embedded program memory is included for the storing of custom application data/libraries. There is a built-in single or dual axis high-g range accelerometer to support all market available wheel sensor auto-location functionalities.
The combination of minimal footprint and high degrees of integration offered by the MLX91804 means that a significant reduction in PCB size can be realised, and the low power consumption (in sleep mode as well as when fully operational) permits a downsizing of the specified battery. The result can be a smaller size and lower weight sensor module. Together with high-g range and fast data acquisition accelerometer, it also represents a step closer to the tyre mounted sensor (TMS) implementations that automotive Tier 1 suppliers are looking to use in the future. Precision and low power fast pressure measurements allow extra new features to be implemented such as tyre filling assistant without a visible impact on battery life. The -40°C to 125°C operational temperature range and strong resilience to shock (10000g) allow the MLX91804 to deal with a harsh in-tire environment.