Automotive-grade, ISO26262-compliant dual magnetic position sensors
Six devices in the AS5270A/B series are aimed at automotive applications including brake and gas pedals, throttle valve and tumble flaps, steering wheel position, chassis ride-height, Exhaust Gas Recirculation (EGR) valves, fuel-level measurement systems, and 2/4 wheel drive switching.
The devices are 0 to 360o rotary magnetic position sensors, that provide contactless high resolution, absolute angle measurements. The AS5270A/B were developed as SEooC (Safety Element out of Context) devices, as defined per the ISO26262 functional safety standard specification.
The AS5270A/B magnetic position sensors provide on-chip full datapath diagnostics, that test the entire device, from the Hall sensor front end, through the DSP engine that converts raw measurements of magnetic field strength into sine and cosine vectors, to the back-end interfaces and pins.
The AS5270A/B are stacked and aligned dual-die devices, AEC-Q100 Grade 0 qualified and come in MLF-16 surface mount packages for high-reliability and redundant operations. Separate package pins are provided for each die in order to avoid electrical fault in the device from affecting both dice.
With an internal 14-bit (0.22-degree) resolution front-end core Hall sensor array, the AS5270A/B devices provide true 12-bit output resolution. The high sensitivity Hall sensor front-ends also enable the devices to work with small, lower cost target magnets and support a wide magnetic field strength input range of 10-90 mT.
The AS5270A provides an analogue output, and the AS5270B provides either a digital SENT (Single Edge Nibble Transmission) or PWM (Pulse Width Modulation) output that is user-programmable.
The AS5270A/B position sensors operate off of a 5V supply voltage, and the supply and output pins are protected against overvoltage up to +20V. The supply pins are protected against reverse polarity up to –20V.
The AS5270A/B devices are immune to magnetic stray fields, thus ensuring highly accurate and repeatable measurements even in the nosiest of magnetic environments. This results in very reliable performance and reduced system cost, since there is no need for sophisticated shielding that is typically required by competitive magnetic position sensor ICs.
The AS5270A/B magnetic position sensors are priced from $3.98 for AS5270A/B (1.000). Evaluation boards for the AS5270A/B are available from the ams ICdirect online store.
ams; www.ams.com
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