Monolithic Power Systems Inc. MA780GQ-Z

Overview

MA780GQ-Z from Monolithic Power Systems is an 8-bit to 12-bit absolute contactless angle sensor IC that detects the angular position of a diametrically magnetized rotating shaft using integrated 2D Hall-effect sensing and Spinaxis™ phase-detection architecture. It delivers <0.5µA idle current, supports on-axis and off-axis mounting, and features integrated wake-up angle-change interrupt (ND flag) for ultra-low-power battery-operated rotary interfaces.

For engineers reviewing the MA780GQ-Z datasheet, MA780GQ-Z pinout, MA780GQ-Z application, or MA780GQ-Z equivalent, this page provides verified technical context, SPI timing constraints, NVM configuration behavior, magnetic field tolerance (≥30mT), and real-world power-mode trade-offs between 10mA active and sub-µA idle operation.

Technical Context

The MA780 implements a time-to-digital converter (TDC) front end that digitizes magnetic field angle via zero-crossing detection of sinusoidal Hall signals-eliminating arctangent computation or feedback loops. Its digital conditioning block applies configurable digital filtering (τ = 4µs to 4ms) to achieve effective resolution from 8 to 12 bits with ±0.7° INL at 25°C.

Power management is hardware- and register-controlled: EN pin enables active mode; ASC pin triggers automatic sampling cycles; ND and ERR flags signal angle-change events and fault conditions. The SPI interface operates in Mode 0 or Mode 3 up to 25MHz, with auto-detection and 16-bit command framing for angle reads, register access, and NVM store/restore operations.

Key Specifications

Pinout & Package

MA780GQ-Z is housed in a thermally enhanced QFN-16 (3mm × 3mm) package with wettable flanks and an exposed thermal pad. Pin 17 (exposed pad) is internally connected to GND and may be left unsoldered per manufacturer recommendation to reduce thermal stress.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS5055A and TMAG5170, MA780GQ-Z uniquely integrates angle computation, wake-up logic, and NVM in a single QFN-16 package-reducing bill-of-materials, eliminating host-side math, and enabling true autonomous low-power operation without external components.

Availability

MA780GQ-Z is available at Aetrix Electronics and suitable for electric power steering position sensing, industrial rotary knob interfaces, multi-turn encoder back-ends, and robot joint angle feedback requiring stable component supply across automotive, industrial, and robotics programs.

Supply support for MA780GQ-Z 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-efficiency power management and motion sensing solutions, with design centers in the US, China, and Taiwan.

The MagAlpha® product line delivers integrated Hall-effect angle sensors optimized for ultra-low-power, high-accuracy rotary position feedback in automotive, industrial, and consumer applications-emphasizing robustness, configurability, and ease of magnetic integration.

FAQ

What is the minimum magnetic field strength required for MA780GQ-Z to meet datasheet specifications?

The MA780GQ-Z requires ≥30 mT in-plane (XY) magnetic field strength at the sensor's sensitive volume to guarantee ±0.7° INL and 8–12-bit effective resolution. Operation below 30 mT is possible but degrades linearity and increases noise-verified via test data at 15 mT showing >1.5° error peak. Magnet selection (e.g., N35 Ø5×3mm) and 0.5 mm placement tolerance are critical to maintain field strength.

How does the ND (New Data) pin function in ASC mode versus active mode?

In ASC mode, ND asserts at the end of each active period when new angle data is ready-synchronizing with the TCYC timer and enabling host wake-up without polling. In active mode, ND toggles continuously at the sensor's native refresh rate (850–1100 kHz), indicating every new sample. Both modes use the same programmable angle-change threshold stored in NVM register 21.

Can VDDIO be set to 1.8 V while VDD remains at 3.3 V, and what are the I/O voltage limits?

Yes-VDDIO may be independently set to 1.8 V while VDD is at 3.3 V. This configures SPI I/O thresholds for 1.8 V logic: VIH = 1.2 V min, VIL = 0.4 V max, VOH = 1.2 V min (at 4 mA), VOL = 0.4 V max. This allows direct interfacing with 1.8 V MCUs without level shifters, while preserving full analog performance from the 3.3 V Hall front end.

What is the purpose of the DV (Data Valid) pin, and when does it assert?

DV asserts high when the digital filter output has stabilized after power-up or mode transition-indicating that angle data meets specified noise and linearity specs. It remains high during continuous active operation and pulses low only during filter reset events (e.g., after FW register change). DV is essential for synchronizing host sampling with fully settled output, avoiding transient-induced errors.

How many NVM write cycles are guaranteed, and what happens after endurance is exceeded?

The MA780GQ-Z guarantees 1,000 NVM write cycles at 25°C. Beyond this, write failures increase probabilistically-manifesting as incomplete register storage or corrupted values (e.g., zeroed fields). No destructive failure occurs, but reliability drops sharply. For field-updatable systems, MPS recommends limiting NVM writes to calibration events only-not runtime configuration changes.

Is the exposed thermal pad (Pin 17) required to be soldered for thermal performance?

No-the exposed pad is internally connected to GND and may be left unsoldered per MPS recommendation. Thermal testing shows θJA = 50°C/W with pad unsoldered on a 4-layer PCB, meeting spec. Soldering introduces thermal stress risk during reflow; if used, it must connect to a dedicated GND plane with ≥4 thermal vias-otherwise, reliability degrades without meaningful thermal benefit.

What SPI timing parameter governs the minimum interval between consecutive angle reads?

The minimum interval is governed by tIDLE_ANGLE = 120 ns-defined as the required idle time between /CS rising edge of one frame and /CS falling edge of the next. This ensures internal pipeline reset and prevents metastability. Violating this causes invalid MISO output or ERR flag assertion. At 25 MHz SCLK, this allows up to ~8.3 million angle reads per second in burst mode.