Melexis automotive position sensor with SENT protocol lowers cost and improves performance under hood

July 30, 2009 - Ieper, Belgium. SENT protocol for Engine Management devices gains support with launch of first fully integrated SENT rotary position sensor IC, MLX90324 by Melexis.

High temperature performance and integrated support for the SENT (Single Edge Nibble Transmission) characterize the new MLX90324. Under-hood position sensor applications like EGR, manifold actuation, diesel throttle body, drive-by-wire pedals and other rotary, high precision position sensors become simpler, more reliable and more cost effective. The increased demand for sensors to meet new green standards in engine design can be well supported by Melexis MLX90324.

This newest member in the Triaxistm family extends the features of previous award winning Triaxistm rotary position sensor ICs. The MLX90324 implements the SENT protocol–also known as SAE J2716-Apr07 directly on chip for reporting functions and gains improved performance at high temperature. Additionally the IC features improved diagnostics of broken tracks (for analog output operating modes) along with an enhanced PWL (piece-wise-linear) back-end calibration for the output transfer characteristic.

The SENT protocol has been initiated by General Motors and several partners in 2005. Subsequent development by an SAE (Society of Automotive Electronics) Workgroup resulted in the establishment of reference standard SAE J2716. This standard is in production vehicles and meets the goal of efficient, lower cost, higher performance communication protocols in demanding, mission critical functions for Engine Management. This IC’s implementation retains both the option for analog communication alongside support for SENT allowing maximum flexibility in supply chain logistics.

Vincent Hiligsmann, Product Marketing Manager of Triaxis at Melexis comments: “The SENT protocol motivation is to modernize and standardize the interface between the numerous remote sensors (position, pressure, mass airflow, temperature…) and the EMS ECU (Engine Management System Electronic Control Unit). The historical pure analog sensor is no longer aligned with the modern mixed signal sensor IC featuring advanced DSP (Digital Signal Processing).” Hiligsmann continues: “SENT brings a viable alternative as a point-to-point digital protocol with a short (less than 1 ms) telegram of 8 nibbles (32 bits) including sensor data, diagnostic information and CRC. The overhead at both sides , sensor and ECU, is fairly limited while analog buffer, broken-track diagnostic, D/A (sensor) and A/D (ECU) converters are no longer needed. However, like any standard, SENT will only exist if it gets used and spread through the industry. On the sensor side, MLX90324 is already an important contribution to this spread.”

The Swiss automotive motor manufacturer Sonceboz (www.sonceboz.com), has already adopted the MLX90324. “Our engine control actuators are all equipped with an integrated rotary position sensor. We are gradually moving from the linear Hall sensors to the Triaxis products as they offer better performance (especially at high temperature) combined with excellent possibilities of compact integration. We use the MLX90324 as it allows Sonceboz to propose either Analog or SENT output to the final user. Sonceboz is proud to be one of the pioneers offering actuators featuring the SENT reporting protocol.”, says Dr. Marc-Olivier André, Business Unit Manager “Engine Controls” at Sonceboz.

Vincent Hiligsmann, Marketing Manager for the Position Sensors concludes: “The MLX90324 shows the Melexis’ commitment to stay continuously at the leading-edge for the non-contacting automotive position sensor. It is the first IC we release in the next generation of our award winning Triaxistm magnetic sensor family”

Similar to the other Triaxis products, the MLX90324 has successfully passed the qualifications based on AEC-Q100 (Grade 0) and including an endurance test (HTOL – High Temperature Operating Lifetest) of 500 hours/160Deg.C. followed by 2000 hours/150 Deg.C.