Simple solution for rotary position sensing

The MLX90316 is a monolithic, programmable Triaxis Hall IC designed for absolute non-contacting 360 degree rotary position sensors

Melexis introduces an absolutely simple solution for rotary position sensing: the MLX90316 is a monolithic, programmable Triaxis Hall IC designed for absolute non-contacting 360 degree rotary position sensors.

In combination with an inexpensive, ordinary magnet, the MLX90316 simplifies the angular position sensing challenges found in many automotive and industrial applications.

Ideal examples of applications for this revolutionary technology include: accelerator and brake pedal position sensors; throttle position sensor; steering wheel position sensor; height sensor; float-level sensor; non-contacting potentiometer; motor-shaft position sensor.

This device represents the initial entry of a family of products resulting from the combination of Melexis automotive Mixed Signal CMOS and the patented integrated magneto-concentrator (IMC) technology of Sentron.

Melexis acquired Sentron, a Swiss high tech development company, in February 2004.

This combined magnetic sensing technology is being presented as Triaxis technology.

With IMC, both components of flux density parallel to the IC surface are measured by the Triaxis Hall sensor front-end.

A diametrally magnetised magnet rotating above the sensor induces sine and cosine (quadrature) signals.

A smart Digital Signal Processing (DSP) core computes a high accuracy angular information from the raw sine and cosine signals.

The core controls also numerous self-diagnostic and on-chip monitoring modes.

"In comparison with position sensors based on conventional linear Hall ICs, the performance of the MLX90316 is intrinsically higher due to the reduced impact of the thermal and lifetime IC sensitivity variations and magnetic flux density variations resulting from the magnet and magnetic circuit elements" said Vincent Hiligsmann, Melexis Automotive Sensor Product Marketing Manager.

"Furthermore, all the manufacturing and thermal tolerances are compensated at the IC level.

MLX90316 simplifies the realization of cost-effective, small, compact but robust rotary position sensor applications" added Hiligsmann.

The computed angle is either available as: an analogue output voltage from a ratiometric 12 bit D/A converter a pulse-width modulation (PWM) output signal (12 bits) with programmable frequency (100 Hz up to 1000 Hz).

a digital serial protocol (14 bits signal + diagnostic).

The output transfer characteristic is fully programmable through adjusting the offset and the gain as well as clamping level, slope polarity or PWM frequency.

All programming steps are done in the final application though the connector (supply, ground, output) by using the Melexis programming unit PTC-04.

No dedicated programming connections or clock synchronisation schemes are necessary.

MLX90316 output can reflect a complete 360 degree revolution but it is also suitable for application with limited angular span.

This rotary position sensor IC is available in SOIC-8 (single die) or in the Melexis full-redundant construction featuring 2 isolated dies in a TSSOP-16 housing.

Both packages are compliant with Lead-Free and RoHS regulations.

MLX90316 is qualified for the harsh automotive environment.

It is already designed in numerous applications and it has recently been released in series production for an accelerator pedal programme at a European vehicle manufacturer.

After the initial revolution of magnetic sensing by the world's first programmable linear Hall sensor in 1996 (MLX90215) this MLX90316 starts a complete revolution that can be sensed simply and absolutely.

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