Brushless resolver MLX90381

motorrobust

Description
The MLX90381 is a 3D magnetic pico-resolver IC (Sin/Cos) for absolute angular position measurement and very high electrical rotational speeds (>50,000 e-rpm at Hall plates). It is a monolithic contactless Triaxis® Hall sensor sensitive to magnetic flux density on X, Y and Z axes. Two selectable axes map to the two high-speed ratiometric analog outputs, enabling on-axis and off-axis (through-shaft) position sensing when used with a moving permanent magnet. The device supports compact motor modules with on-board programmability and automotive-grade qualifications.

Key capabilities

• Triaxis® 3D Hall sensing with selectable output axis pairs (X/Y, X/Z, Z/Y)
• Sine and cosine ratiometric analog outputs for absolute angle reconstruction
• High-speed output refresh: 2 µs update rate
• Capable of measuring electrical speeds >50,000 e-rpm (measured at Hall plates)
• On-board programmable via I²C using two application pins (no external programmer required)

Top features

• Compact DFN-6 package (2.0 × 2.5 mm) minimizing PCB area
• Onboard programming through I²C; configurable per module
• ISO 26262 ASIL B SEooC readiness
• AEC-Q100 qualification for automotive use
• Programmable sensitivity ranges: mid field (10 … 70 mT) and high field (40 … 160 mT)
• Operating supply: 3.3 V or 5 V
• Wide operating temperature range: -40 °C to 160 °C

Applications

• Absolute rotary position sensing
• Brushless motor control (PMSM/BLDC)
• Field-oriented control (FOC) systems
• Automotive actuators and valves: e-valves, thermo valves, EPS, brake systems (improved low-speed accuracy and stall detection)

Package and integration
The MLX90381 is supplied in a DFN-6 (LW) single-die package with matte-tin wettable flanks and is RoHS compliant. Typical implementations require minimal external components (three capacitors), reducing BOM and board area. Axis sensitivity and filter bandwidth are configurable on-board to align analog outputs with companion ADC ranges.

Evaluation and design
An evaluation board (EVB90381) is available for rapid prototyping and system evaluation of MLX90381 in motor control applications.

Technical specifications

• Model: MLX90381
• Technology: Triaxis® 3D Hall sensing
• Outputs: Analog sine and cosine (ratiometric)
• Output refresh rate: 2 µs
• Maximum measurable electrical speed: >50,000 e-rpm (at Hall plates)
• Supply voltage: 3.3 V or 5 V
• Operating temperature: -40 °C to 160 °C
• Selectable magnetic axes: X/Y, X/Z, Z/Y
• Programmable sensitivity: mid field 10 … 70 mT; high field 40 … 160 mT
• Onboard programming: I²C via two application pins
• Package: DFN-6 (LW), 2.0 × 2.5 × 1.0 mm, single die, RoHS, matte-tin wettable flanks
• External components: typical implementation requires three external capacitors
• Automotive: AEC-Q100; ISO 26262 ASIL B (SEooC)
• Typical applications: absolute rotary position, BLDC/PMSM control, FOC, automotive valves and actuators