Electronics Weekly Electronics Design & Components Tech News
Intended for automotive engine management, the mems-based devices measure absolute pressure across 1 to 4bar.
- MLX90824 delivers a SENT protocol digital output
- MLX90822 has an analogue voltage output voltage
“An accuracy of +/-0.5% of full scale is maintained over the course of the sensor’s working lifespan,” said company product manager Laurent Otte. “This accuracy is not impacted by the sensor integration thanks to the PCB-less packaging.”
The SENT output MLX90824 adds a pre-calibrated NTC thermistor input which “allows customers to interface their NTC through the pressure sensor without end-calibration”, said Melexis.
Protection for ±40V is included, and operation if over -40 to + 160°C (+170°C short-term).
Sensing is via a micro-machined diaphragm bonded around a cavity etched into the silicon substrate. This traps a reference vacuum. Piezo-resistive elements implanted into the diaphragm implement a Wheatstone bridge, whose signal is conditioned by subsequent circuits, with a 16bit DSP applying temperature compensation.
The parts are developed as a ‘safety element out of context (SEooC) in accordance with ISO 26262, supporting ASIL B integration for the SENT MLX90824 and ASIL A for the analogue MLX90822.
“Last but not least for motorcycles or any equipment running on small engines such as chainsaws and lawn mowers, 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 three times faster than any other pressure sensor ever made by Melexis,” it said.
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