A sensor chip that takes automotive engine management to new heights of precision

Melexis, a global microelectronic engineering company, announced the launch of two relative pressure sensor chips that provide superior robustness in harsh media. These two market-ready ultra-precision pressure sensor chips complete the Melexis PCB-free platform product line. With this family of pressure sensor chips, customers and Oems will be able to make all their internal combustion engine management applications more environmentally friendly through a single modular technology. In order to further simplify the customer's manufacturing process, the series of components have been factory calibrated, of course, the customer can also be required to recalibrate.

MLX90823 (analog output) and MLX90825 (digital SENT output) are two relative pressure sensor chips that support either gauge mode (corresponding to atmospheric pressure) or differential mode (with two variable pressure levels). Unlike absolute pressure sensor chips, they can measure the pressure difference between the two sides of the sensor chip. These factory-calibrated devices are designed to measure pressure ranges in the 0.1 to 1.5bar range.

These two new pressure sensor chips could take the automotive industry to the next level of measurement accuracy. Obtaining stable and accurate pressure and temperature data enables full lifecycle management of the engine, which can help Oems reduce emissions from the last generation of internal combustion engine vehicles. Melexis' line of pressure sensor chips supports plug-and-play functionality for a wide range of internal combustion engine management applications. These include:

● Fuel steam and crankcase ventilation applications: Ensure that fuel steam in the tank or gas leaking through the piston is returned to the combustion chamber to prevent them from venting into the atmosphere.

● EGR, GPF/DPF: reduce nitrogen oxide emissions by sensing the amount of recirculated exhaust gas at the engine intake and trapping residual particulate matter in the exhaust filter.

● Secondary air injection (SAI) : It can quickly preheat the catalytic converter through "secondary air injection", so that in various application scenarios (including engine cold start) vehicle emissions can be maintained within the limits.

● (T) MAP: Monitor the air entering the engine and accurately adjust the fuel volume to reduce fuel consumption.

Laurent Otte, Melexis Senior product Line Manager, said: "With a complete PCB-free portfolio, Oems are able to cope with a wide range of stressful applications. Customers benefit from highly reusable platform solutions that reduce development costs and shorten time to market."

Both MLX90823 and MLX90825 integrate sensors, signal processing circuits, digital hardware, voltage regulators, SENT or analog output drivers, and all basic passive devices. MLX90825 supports pre-calibrated negative temperature coefficient (NTC) thermistor inputs (SENT outputs). No terminal calibration is required when the customer connects the NTC via the pressure sensor chip. The chip integrates excellent overvoltage (+40V) and reverse voltage (-40V) protection mechanisms. The technology makes trucking more environmentally friendly thanks to its excellent range of protection. The range of operating temperature of the pressure sensor chips is -40℃ to 160℃, and can even withstand temperatures up to 170℃ for a short time, thus supporting the trend of miniaturization of engine structure.

The MLX90823 and MLX90825 MEMS sensing elements consist of a micromechanical sensing film etched onto a silicon wafer substrate. The sensing membrane can respond to changes in pressure. The piezoresistive elements implanted in the sensor film can be connected to form a Wyeth bridge to generate a signal. An onboard front-end electronic component then amplifies the signal and converts it into a digital signal. 16 bit digital signal processing (DSP) is responsible for temperature compensation. Finally, the results are provided via SENT output or simulated output.

Both MLX90823 and MLX90825 are developed as separate safety units (SEOOCs) and conform to ISO 26262 standards. MLX90825 (SENT output) meets ASIL Level B requirements and MLX90823 (analog output) meets ASIL Level A requirements.

"Now, our customers can choose from a range of PCB-free sensor chips that support differential mode, giving them the ability to pursue new opportunities in the market." "Customers benefit from this unique modular technology for demanding applications such as diesel and gasoline particle filters," said Karel Claesen, product manager for pressure sensor chips at Melexis.