Monolithic Power Systems Inc. MA850GQ-P

Overview

MA850GQ-P from Monolithic Power Systems is an 8-bit contactless absolute angle encoder IC that replaces potentiometers and rotary switches in manual HMI controls. It delivers PWM output with ±1.1° INL over -40°C to +125°C, supports programmable magnetic field thresholds for push/pull button detection, and operates at ≤200 rpm shaft rotation speed in human-interface applications.

For engineers reviewing the MA850GQ-P datasheet, MA850GQ-P pinout, MA850GQ-P application, or MA850GQ-P equivalent, this page provides verified technical context on its Spinaxis™ phase-detection architecture, 50 kHz PWM timing, SPI register programming model, and dual magnetic threshold logic outputs (MGH/MGL) used for mechanical actuation sensing.

Technical Context

The MA850GQ-P uses Spinaxis™ phase-detection-measuring time between zero-crossings of a Hall-generated sinusoid and a reference clock-to compute angle without arctangent computation or feedback loops. Its front-end digitizes angular position at 1 MHz before digital filtering.

It implements two independent magnetic field strength comparators (MGHT/MGLT), each configurable via 3-bit values in Register 6, with 6 mT hysteresis and -600 ppm/°C temperature drift. The PWM output has fixed 50 kHz nominal frequency, 10–90% duty cycle range, and 8-bit resolution mapped linearly to 0–358.6°.

Key Specifications

Pinout & Package

MA850GQ-P is housed in a QFN-16 (3 mm × 3 mm) package with exposed thermal pad. Pin 17 (exposed pad) must be connected to GND for optimal electrical, thermal, and mechanical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar absolute magnetic angle encoder applications.

Compared with AS5600 and TMAG5170, MA850GQ-P uniquely integrates PWM generation, dual magnetic threshold comparators, and NVM-based configuration in a QFN-16 package-reducing system-level component count and enabling drop-in replacement of electromechanical potentiometers.

Availability

MA850GQ-P is available at Aetrix Electronics and suitable for rotary knob control interfaces, automotive HVAC systems, white goods dials, and industrial panel controllers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MA850GQ-P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance power management and sensing solutions, with design centers in the US, China, and Taiwan.

The MagAlpha® family-including MA850GQ-P-is engineered for contactless angular position sensing in human-machine interfaces, targeting cost-sensitive, high-reliability applications where mechanical wear and ESD susceptibility must be eliminated.

FAQ

What is the recommended magnet configuration for MA850GQ-P?

A diametrically magnetized NdFeB cylinder (N35 grade, Ø5 × 3 mm) mounted on the shaft end with ≤1.0 mm air gap is optimal. Field strength must remain between 30–100 mT at the sensor's sensitive volume-centered within 50 µm of the QFN package surface-for full 8-bit linearity and ±1.1° INL performance.

How is zero-angle calibration performed on MA850GQ-P?

Zero angle is set by writing a 16-bit complementary value to Registers 0 and 1 (Z[15:0]) via SPI. For 20° mechanical zero, write 0xF1C7 to Reg 0 and 0xFE01 to Reg 1. The device stores this in on-chip NVM and applies it automatically at power-on-no external calibration routine is needed.

Why does the MGL output exhibit short pulses, and how should they be handled?

MGL generates 1.3–1.5 µs glitches near 44°, 138°, 224°, and 318° due to internal signal routing. Use the dual-read workaround: sample MGL twice 2–100 µs apart; only accept transitions where both readings match. Alternatively, invert MGH or compute corrected MGL = !(MG1L | MG2L) from Register 27 bits 5–4.

Can MA850GQ-P operate without connecting the exposed thermal pad?

Yes-electrical operation is functional with the exposed pad floating-but thermal resistance θ_JA degrades from 50°C/W to >75°C/W, increasing junction temperature by ~15°C at full load. For automotive or industrial use above 85°C ambient, soldering the pad to a GND plane is mandatory to maintain reliability and meet 125°C T_J limit.

What SPI modes does MA850GQ-P support, and how is mode selection handled?

MA850GQ-P auto-detects SPI Mode 0 (CPOL=0, CPHA=0) and Mode 3 (CPOL=1, CPHA=1) on power-up by sampling SCLK idle state. No configuration register setting is required. Maximum SCLK frequency is 25 MHz; minimum is unrestricted. All transactions use MSB-first 16-bit framing.

Is the PWM output ratio-metric to VDD, and how does supply variation affect angle accuracy?

No-the PWM duty cycle is angle-encoded and independent of VDD. However, magnetic threshold levels scale linearly with VDD/3.3 V (e.g., MGHT = 112 mT at 3.3 V becomes 102 mT at 3.0 V). Angle accuracy remains unaffected because the core Spinaxis™ phase measurement is supply-insensitive.

Does MA850GQ-P require external components for basic operation?

Only a 1 µF ceramic decoupling capacitor between VDD and GND, placed within 2 mm of pins 13 and 8, is required for stable operation. All other functions-including SPI pull-ups/downs, PWM filtering, and button logic-are self-contained. No external resistors or op-amps are needed for default configuration.