IN Brief:
- The HAR 3025 combines two independent Hall-sensor dies in a 4 × 4mm QFN24 package, with six Hall plates per die.
- The ASIL D-ready device provides redundant analogue sine/cosine outputs, stray-field compensation and independent fault diagnostics.
- Samples are available, with production planned for the first half of 2027.
TDK has introduced the Micronas HAR 3025, a redundant magnetic position sensor combining two independent Hall-sensor dies within a 4 × 4mm QFN24 package. The device provides separate analogue sine/cosine outputs and diagnostic functions for automotive and industrial motor control applications, including electrically actuated steering, braking and traction systems.
Announced on 13 October, the HAR 3025 extends the company’s fast angular position sensor family with a dual-die architecture designed for applications requiring continued sensing after a single channel failure. Samples are available, with production scheduled for the first half of 2027. TDK has not announced a completed vehicle integration programme or confirmed customer production volumes for the new component.
The two dies are stacked within the same package, with their centres of magnetic sensitivity aligned so that both measure substantially the same target field. Their independently generated position signals can be compared by an external electronic control unit, allowing the controller to identify discrepancies that may indicate a fault in one sensing channel.
Redundant measurement is particularly important in electrically actuated steering and braking systems, where a position error can influence the motor’s response to a control command. Comparing independent measurements provides a means of detecting certain failures, although the complete system must also account for common-cause faults, power supplies, external wiring and the behaviour of the actuator itself.
TDK developed the HAR 3025 as a Safety Element out of Context under ISO 26262:2018 and describes it as ASIL D-ready. The company states that each die meets ASIL D metrics and that the unaffected die remains operational if the other fails. Those characteristics support the development of safety-related control systems, but component-level readiness does not establish the functional-safety compliance of a finished vehicle or industrial machine.
Each sensing die incorporates six horizontal Hall plates and internal signal processing intended to compensate for unwanted magnetic fields. TDK specifies stray-field robustness in accordance with ISO 11452-8:2015, addressing interference that can arise from high motor currents, power cables and nearby electrical equipment. Compensation is performed within the sensor rather than relying solely on external shielding or unusually strong target magnets.
Magnetic interference can affect position measurement because the Hall elements respond to the magnetic field present at the sensing location. A field generated by adjacent equipment may be superimposed on the useful field from the target magnet, changing the apparent position if the sensing arrangement cannot distinguish the two. The HAR 3025 uses its Hall-plate configuration and processing to reduce susceptibility to such disturbances, although the complete magnetic installation must still be evaluated against expected operating conditions.
The sensor supplies sine and cosine analogue signals in differential or single-ended configurations. An external microcontroller or electronic control unit converts these signals into an angular position, using the relationship between the two channels to calculate the target magnet’s orientation. The device therefore supplies the underlying position signals rather than communicating a finished angle through a digital serial interface.
Signal-path configuration includes adjustments for gain, offset, zero-angle position, orthogonality and bandwidth. Programming is performed through the sensor’s output pin, avoiding the need for a separate programming connection. Four selectable amplifier bandwidths extend from 4.6kHz to 70.5kHz, allowing the measurement response to be adapted to the speed and noise requirements of the motor-control system.
Bandwidth selection introduces a practical trade-off between signal response and noise. A higher bandwidth can preserve faster variations in the magnetic signal, but may also admit more noise into the measurement path. Lower bandwidth settings can reduce unwanted signal variation while increasing response delay. The appropriate configuration consequently depends on motor speed, control-loop requirements and the filtering performed by the receiving electronics.
TDK specifies a total angular error of no more than 0.6 degrees when static end-of-line compensation is applied. The figure can be reduced to 0.1 degrees with external dynamic compensation, making the smaller value conditional on additional processing outside the sensor. Configurable sine/cosine signal delay ranges from 4.16 to 42.69 microseconds, with a maximum specified delay-time jitter of 2ns RMS.
Integrated diagnostics monitor supply voltage, clock operation, temperature, Hall signal processing, configuration registers and EEPROM. When a fault is detected, the affected die places its outputs in a high-impedance state. External pull-up or pull-down resistors allow the receiving controller to recognise that condition rather than interpret it as a valid measurement. Passive wire-break detection provides another mechanism for identifying connection faults.
Electrical specifications include a supply voltage range from 3.0V to 5.5V and a junction temperature range from -40°C to 170°C. The maximum ambient operating temperature is specified separately as 150°C. These temperature limits describe different operating conditions and cannot be substituted for one another when assessing thermal suitability.
The package incorporates wettable flanks to support automated optical inspection of solder joints during assembly. This feature can assist inspection of connections that might otherwise be difficult to assess visually beneath a leadless package. It does not remove the need for appropriate soldering processes or electrical testing after assembly.
The HAR 3025 follows TDK’s single-die HAL 3025, announced in May 2026. The newer device adds a dual-die arrangement for applications requiring independent sensing channels, rather than representing the first introduction of the underlying fast Hall-sensing technology. Its compact package allows redundant sensing to be considered without necessarily accommodating two separate sensor packages on the circuit board.
Production is planned for the first half of 2027, giving system developers time to assess magnetic geometry, analogue interfaces, diagnostic behaviour and functional-safety requirements using samples. TDK states that operating parameters must be validated for each customer application. Final system qualification therefore remains dependent on the complete actuator, electronics and fault-handling architecture rather than the sensor specification alone.
