Automotive-grade magnetic position sensors with PSI5 interface
From ams (Premstaetten, Austria), AS5172A/B magnetic position sensors feature a two-wire PSI5 interface for fast and secure transmission of their precise rotary position measurements.
These system-on-chip (SoC) devices are 0° to 360° contactless rotary magnetic position sensors which provide absolute angle measurements in 14-bit resolution. The sensors have been developed as SEooC devices according to the automotive safety standard ISO26262, and feature extensive on-chip self-diagnostic systems. This suits the sensors to safety-critical automotive applications, enabling a vehicle system to meet the highest ASIL safety level requirements.
The PSI5 interface in the AS5172A/B parts conforms to the latest standards, as set by the PSI5 specification versions 1.3 and 2.1. AEC-Q100 qualified. The AS5172A/B devices support automotive remote position sensing applications including brake and gas pedal position sensing, throttle valve and tumble flaps, steering angle sensors, chassis ride height sensors, exhaust gas recirculation (EGR) valves, and fuel-level measurement systems.
Based on Hall sensor technology, the AS5172A/B devices measure the orthogonal component of the flux density over a full-turn rotation and compensate for external stray magnetic fields with a robust architecture centred around a 14-bit (0.022° resolution) sensor array and analogue front end. The AS5172A/B can also be programmed to support a sub full-turn angular range of motion as small as 0° to 10°, to achieve the best resolution for the application.
The high sensitivity Hall sensor front ends also enable the devices to work with small, low cost target magnets and support a wide magnetic field input range of 10-90 mT. Only a simple two-pole magnet rotating over the centre of the package is required to provide a nearly instant indication of the magnet’s absolute angular position. The magnet may be placed above or below the device.
The AS5172A/B operate over a supply voltage range of 4V to 16.5V, and support up to +20V of overvoltage protection. Supply pins are protected against reverse polarity up to -18V. The AS5172A/B is programmed over the device’s VDD pin via a single-wire UART-over-PSI5 interface, minimizing the number of pins on the application programming connector. The AS5172 is available in a TSSOP14 package (AS5172B) and in an SIP package (AS5172A). The SIP package (System in Package) integrates the AS5172 sensor die together with the decoupling capacitors to yield improved ESD and EMC performance, eliminating the need for a PCB, and reducing overall system sensor costs. The AS5172A and AS5172B operate over a -40°C to 125°C and -40°C to 150°C temperature range, respectively. Unit pricing is $3.28 (AS5172A) or $2.69 (AS5172B), both (1000). Evaluation boards for the AS5172A/B are available from the ams ICdirect online store. F
ams; www.ams.com/Position-Sensors/AS5172A or www.ams.com/Position-Sensors/AS5172B
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