The SMP290 from Bosch is a fully integrated, Bluetooth-enabled single-chip solution designed for tyre pressure monitoring systems (TPMS).
The module contains a Bluetooth Low Energy interface, a microcontroller, a MEMS pressure and temperature sensor, a 2-axis MEMS acceleration sensor and a voltage measurement function. Diagnostics and communication are possible in both directions via the standardised BLE 5.4 interface. Measurement data or updates can be encrypted for transmission with the customer-specific application software. As the BLE standard is already used in vehicle components such as infotainment or radio keys, the sensor module aligns perfectly with the vehicle’s radio landscape.
Tire pressure sensors play a decisive role in the service life of tyres, as well as in fuel consumption, ensuring the road safety of vehicles. The SMP290 has a sensor readout ASIC whose core comprises the energy-efficient 32-bit MCU ARC EM6 with FPU, DMA and cache for minimum power consumption. The 64kB RAM ensures a reliable start. Additionally, the SMP290 contains an analog front end for the pressure sensor, temperature measurement via on-chip diode, the x- and z-axis acceleration sensor and battery voltage monitoring.
The module implements an advanced power management system on the ASIC with low-power circuits: configurable and high-efficiency DC/DC converter, low-noise bandgap references, low-drop-out regulator, an HF RC oscillator for efficient MCU operation, an accurate low-frequency RC oscillator for sleep mode control, and a low-power, low-frequency RC oscillator for deep sleep mode control. A coordinated digital control system optimizes power consumption and lifetime of the TPMS sensor. Developers can choose between 0, 4 and 6 dBm transmission power.
The sensor module is available in a 3.5mm x 4. mm DFN housing with Wettable Flanks for automatic optical inspection (AOI). It impresses developers with the low number of external components required and the correspondingly low TCO.
Regarding security, the SMP290 offers a low-power hardware implementation of AES-128 encryption. In addition, it performs a cyclic redundancy check (CRC) of all parameters consumed by the digital signal chain, traceability and stored runtime data.
