Melexis introduces a new series of integrated pressure sensors. They are intended for use in automotive engine management. The MLX90824 determines the absolute pressure, then delivers a digital output signal using the SENT protocol whereas the brother product MLX90822 provides an analog output voltage. These factory calibrated devices measures pressure spans from 1 to 4 bar.
For motorcycles or any equipment running on small engines such as chainsaws, lawn mowers among others it is essential to have a sensor with a very fast update rate and step response. The MLX90822 addresses that need with an output step response 3 times faster than any other pressure sensor ever made by Melexis.
The MLX90824 and MLX90822 consist of a sensor readout circuit, digital hardware, voltage regulators and SENT or analog output drivers, plus all the essential passive components. A pre-calibrated NTC thermistor (negative temperature coefficient) input is available for the MLX90824 (SENT output). This allows customers to interface their NTC through the pressure sensor without end-calibration. Superior overvoltage (+40 V) and reverse voltage (-40 V) protection mechanisms are incorporated. Thanks to this protection range, trucks benefit from this technology to get greener. These pressure sensors have an operating temperature range that spans from -40°C to 160°C. They can even be exposed to 170°C temperatures for a short period of time, supporting downsized engine architectures.
The MEMS, sensing element of the MLX90824 and MLX90822, consists of a micro-machined diaphragm. It is bonded around a cavity that has been etched into a silicon substrate. This cavity contains a reference vacuum. The diaphragm reacts to any change in the ambient absolute pressure. Piezo-resistive elements implanted into the diaphragm are configured to create a Wheatstone bridge that generates a signal. The accompanying front-end electronics subsequently amplify the signal and convert it into a digital format. The 16-bit Digital Signal Processing (DSP) undertakes temperature compensation. Finally, the result is provided through a SENT or analog output.
The MLX90824 and MLX90822 have been developed as a Safety Element out of Context (SEooC) in accordance with ISO 26262. It supports ASIL B system integration for the MLX90824 and ASIL A for the MLX90822.
