Magnetic angle sensor has built-in redundancy for ASIL D safety

TAS8240 is designed to operate next to a rotating magnet and contains four pairs of TMR half bridges (four Wheatstone bridges) to provide four separated sine-cosine outputs. “Depending on system architectures, fail-operational concepts can be supported by the new sensor,” according to the company. “System safety levels up to ASIL D can be achieved while offering higher availability of position information, even in case of a failure of one of the output signals.”

There are two package options: a 3 x 3mm QFN16 with wettable flanks for automated soldering inspection, and a 5 x 6.4mm TSSOP16.

Magnets between 20 and 80mT are recommended, and operation is possible up to 130mT with reduced accuracy – abs max is 200mT for five minutes at 25°C.

The bridges are nominally 5kΩ and designed for operation from 3 or 5V.

Readout is intended to be ratiometric with supply voltage, and peak-to-peak output with a 20mT magnet is typically 0.3 x Vcc.

Operation is over -40 to +150°C (ambient), where accuracy is ±1° or better, typically improving to ±0.3° at 25°C. “The angle accuracy of the sensor remains stable at different temperatures and over the sensor’s lifetime,” added TDK.

Application examples include measuring the rotor position in brushless dc motors used for power steering, brake boosting or traction.