Laurent Otte, product line manager, explains why these sensors benefit Melexis customers: "An accuracy of +/-0.5% FS (full scale) is maintained throughout the sensor's lifespan. This accuracy is unaffected by the sensor's integration thanks to the PCB-free encapsulation." The highly accurate and stable pressure measurements enable optimal engine management to ensure fuel savings and reduced emissions.
The MLX90824 and MLX90822 consist of a sensor readout circuit, digital hardware, voltage regulators, and SENT or analog output controllers, in addition to all essential passive components. The MLX90824 features a pre-calibrated NTC thermistor input (negative temperature coefficient) (SENT output). This allows customers to interface their NTC through the pressure sensor without requiring final calibration. Superior protection mechanisms against overvoltage (+40 V) and reverse voltage (-40 V) are incorporated. Thanks to this protection range, trucks benefit from this technology to be more environmentally friendly. These pressure sensors have an operating temperature range from -40°C to 160°C. They can even withstand temperatures of +170°C for short periods, enabling smaller engine designs.
The MEMS sensing element in the MLX90824 and MLX90822 consists of a micromachined membrane. It is bonded around a cavity etched into a silicon substrate. This cavity contains a reference vacuum. The membrane reacts to any changes in ambient absolute pressure. Piezoresistive elements embedded in the membrane are configured to create a Wheatstone bridge, which generates a signal. The accompanying front-end electronics then amplify the signal and convert it to a digital format. 16-bit digital signal processing (DSP) handles temperature compensation. Finally, the result is provided via a SENT or analog output.
The MLX90824 and MLX90822 have been developed as out-of-context safety elements (SEooC) in accordance with ISO 26262. It supports ASIL B system integration for the MLX90824 and ASIL A for the MLX90822.
"The introduction of the EU's Euro 7 emissions standards will have significant implications for internal combustion engine vehicles. Access to stable and accurate pressure and temperature data enables long-term engine management throughout the vehicle's lifespan. This has a positive impact on fuel economy and emissions reduction," says Karel Claesen, Product Manager for Pressure Sensors. "The MLX90824 and MLX90822 are optimized for the latest engine designs and their new operating conditions."
Last but not least, for motorcycles or any equipment powered by small engines, such as chainsaws or lawnmowers, it is essential to have a sensor with a very fast refresh rate and step response. The MLX90822 meets this need with an output step response three times faster than any other pressure sensor manufactured by Melexis.
The MLX90824 and MLX90822 help original equipment manufacturers (OEMs) in their ongoing efforts to reduce emissions and counteract high fuel prices by improving fuel efficiency. They ensure that cars meet the stringent Euro 7 emissions standard, trucks meet the Euro VII standard, and motorcycles meet their respective emissions standards.
