AMS magnetic position sensors fit automotive apps

October 12, 2017

AMS magnetic position sensors fit automotive apps

The AS6172A/B features a two-wire PSI5 interface for fast and secure transmission of their precise rotary position measurements.

AMS recently expanded its portfolio of magnetic position sensors for automotive applications with the introduction of the AS6172A/B, which features a two-wire PSI5 interface for fast and secure transmission of their precise rotary position measurements. The new system-on-chip (SoC) devices meet ISO26262 safety-critical requirements and support 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.

The AS5172A and AS5172B SoCs are 0° to 360° contactless rotary magnetic position sensors which provide absolute angle measurements in high 14-bit resolution. They’ve been developed as SEooC devices, and feature extensive on-chip self-diagnostic system, suiting them for safety-critical automotive applications, enabling a vehicle system to meet the highest ASIL safety level requirements. In addition, 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.

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 centered around a 14-bit (0.022° resolution) sensor array and analog 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°.

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 to 90 mT. Only a simple two-pole magnet rotating over the center 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 4Vto 16.5V, and support up to +20 V of overvoltage protection. In addition, the supply pins are protected against reverse polarity up to
-18 V. The AS5172 is available in a TSSOP14 package (AS5172B) and in an SIP package (AS5172A). The SIP integrates the AS5172 sensor die 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.

The AS5172A/B magnetic position sensors are available immediately in production volumes. Unit pricing is $3.28 (AS5172A) or $2.69 (AS5172B) in quantities of 1000. Evaluation boards are also available.