会社ブログについて ST L3GD20 Low-Power Three-Axis Gyroscope With I2C/SPI Digital Output For Drones

Shenzhen Mingjiada Electronics Co., Ltd. supplies and recycles the ST L3GD20 low-power three-axis gyroscope, featuring I2C/SPI digital output, suitable for drone applications.

The ST L3GD20 is a high-performance, low-power MEMS three-axis digital gyroscope, specifically designed for applications such as motion and attitude detection, inertial navigation and dynamic stabilisation control. The device integrates a high-precision three-axis angular velocity sensing unit and features a universal dual I²C/SPI digital interface. It offers key advantages such as controllable power consumption, adjustable measurement range, high stability and low temperature drift. It is perfectly suited to the attitude estimation and flight stabilisation control requirements of various types of drones, including multirotors, fixed-wing aircraft, small agricultural drones and racing drones, making it a classic core sensor component for drone flight control systems.

I. Core Overview of the L3GD20

The L3GD20 is a fully integrated three-axis MEMS angular velocity sensor capable of simultaneously detecting real-time rotational angular velocity along the X, Y and Z axes. It features a built-in 16-bit high-precision ADC conversion unit that converts analogue motion signals into high-resolution digital output, eliminating the need for additional analogue-to-digital conversion circuits and thereby simplifying flight control hardware design. The device utilises a compact LGA package, which is small in size and highly vibration-resistant, meeting the hardware design requirements for lightweight and miniaturised UAVs. It also supports stable operation across a wide temperature range of –40 °C to +85 °C, enabling it to cope with UAV flight conditions such as high altitudes, extreme temperatures and complex air currents.

The L3GD20’s key advantage lies in its multi-level low-power operating modes. Combined with flexible digital interface configuration, it meets the high-frequency attitude sampling requirements during high-speed flight whilst also accommodating the low-power endurance needs during hovering and standby modes, thereby effectively balancing flight performance with endurance.

II. Core Performance Parameters of the L3GD20

The hardware parameters of the L3GD20 have been specifically optimised to fully meet the core requirements for accuracy, speed and stability in drone attitude sensing. The key parameters are as follows:

- Configurable detection range: Supports switching between three angular velocity ranges—±250 dps, ±500 dps and ±2000 dps—to accommodate different drone models. The low range meets the high-precision detection requirements for stable hovering and slow flight in aerial photography drones, whilst the high range is suited to rapid attitude deviation detection in racing drones and high-speed manoeuvring drones

- High-precision sampling output: Features a built-in 16-bit digital output resolution, with angular velocity noise density as low as 0.011°/s/√Hz and excellent zero-offset stability. It can accurately capture minute changes in the drone’s attitude, including pitch, roll and yaw, providing precise data support for flight controller PID tuning

- High output rate: Maximum output data rate (ODR) of up to 800 Hz, supporting high-frequency attitude data updates, effectively reducing drone flight latency and preventing lag and drift during high-speed manoeuvres and attitude corrections

- Wide operating voltage range: Operating voltage of 2.2 V to 3.6 V, compatible with the 3.3 V power supply systems commonly used in drone flight controllers; no level-shifting circuitry required, ensuring excellent hardware compatibility

- Ultra-low power consumption with tiered control: Current consumption is just 6.1 mA in normal operating mode, as low as 5 μA in sleep mode, and as low as 1 μA in standby mode. It supports dynamic power switching, significantly reducing power consumption during drone standby and hover states, thereby extending the overall flight duration

- Built-in data cache: Features an integrated 32-level FIFO cache capable of buffering attitude data, reducing the frequency of reads by the main control chip, lowering the computational load on the flight controller MCU, and enhancing system operational stability

- Strong environmental adaptability: Featuring vibration- and interference-resistant design with a wide operating temperature range, it can withstand airflow vibrations, airframe vibrations and outdoor temperature fluctuations encountered during drone flight, ensuring stable data output without drift

III. Advantages of Dual I2C/SPI Digital Interfaces

The L3GD20 comes standard with both I2C and SPI universal digital communication interfaces, enabling compatibility with flight control systems of various architectures. It offers exceptional hardware adaptability, meeting the design requirements for all types of lightweight, high-performance flight control systems.

1. I2C Interface

The I2C interface features simple wiring and requires few pins, making it suitable for the hardware design of small, lightweight drones, entry-level aerial photography drones and toy-grade drones. Data transmission requires only two communication lines, and the bus can be shared with other sensor devices such as accelerometers and magnetometers. This simplifies flight controller cabling and saves PCB space, aligning with the trend towards smaller and lighter drones whilst meeting the development requirements for low-cost, streamlined flight control systems.

2. SPI Interface

The SPI interface offers faster communication speeds, greater resistance to interference and lower data transmission latency, making it suitable for scenarios with high demands for real-time performance and stability, such as racing drones, crop-spraying drones and small industrial-grade drones. High-speed SPI communication ensures the stable transmission of high-frequency attitude data at 800 Hz, preventing data packet loss and delays under complex flight conditions, and providing real-time data support for rapid attitude correction, precise stationary hovering and route-based flight.

IV. The L3GD20’s Low-Power Design is Tailored for Drone Applications

Drones impose extremely stringent requirements on power consumption control. The L3GD20 incorporates STMicroelectronics’ proven MEMS low-power architecture and supports dynamic switching between multiple operating modes, specifically addressing the challenge of limited flight endurance in drones.

During high-speed flight and manoeuvring, the device switches to normal operating mode, providing high-frequency three-axis angular velocity data to ensure the flight control system can calculate attitude in real time and execute precise control; during stationary hovering, low-altitude standby or idle states, it can switch to sleep or low-power mode, significantly reducing operating current and minimising power consumption whilst maintaining basic attitude monitoring. Compared to traditional gyroscopes, the L3GD20’s tiered power consumption design reduces the drone’s overall standby power consumption by more than 30 per cent, effectively extending the flight time of drones engaged in long-duration operations such as aerial photography, inspection and crop protection.

V. Core Application Scenarios for Drones

Leveraging its comprehensive advantages of high precision, low power consumption, high stability and universal interfaces, the L3GD20 is widely used in the flight control systems of various civilian and small industrial drones. Its core application scenarios are as follows:

- Multirotor aerial photography drones: Precisely detects changes in the aircraft’s pitch, roll and yaw angles; works in conjunction with an accelerometer to achieve attitude fusion calculations, ensuring stable aerial footage and steady hovering, whilst suppressing flight vibrations and drift

- Small agricultural drones: Adapted to complex outdoor field conditions, its wide temperature range and vibration resistance enable it to withstand interference from field air currents and operational vibrations, ensuring stable output of attitude data to guarantee precise flight paths and uniform spraying

- Racing and obstacle-course drones: With a long-range measurement of ±2000 dps and high-speed output at 800 Hz, it is suitable for detecting flight attitudes during high-speed flips and rapid manoeuvres; low-latency data transmission meets the demands of racing drones for ultra-fast attitude response

- Small inspection drones: Low power consumption supports extended low-altitude inspection operations, whilst highly stable data output ensures precision during fixed-point cruising and route flights, making them suitable for power grid, security and environmental inspection scenarios

- Educational and training drones: Featuring universal interfaces, excellent value for money and simple configuration, these are suitable for university drone training and embedded development teaching scenarios, reducing the difficulty of getting started with flight control development

VI. Summary of the L3GD20’s Advantages

The ST L3GD20 three-axis gyroscope, with its five core features—16-bit high-precision detection, three-level adjustable range, dual I2C/SPI interfaces, tiered ultra-low power consumption, and high stability across a wide temperature range—perfectly meets the core requirements for drone attitude sensing. By balancing high precision with low power consumption, as well as versatility with stability, it not only resolves the issues of insufficient accuracy and excessive drift commonly found in entry-level drones, but also avoids the drawbacks of high power consumption and high costs associated with high-end sensors. Consequently, it has become an exceptionally cost-effective and highly stable core inertial sensor component for flight control systems in small and medium-sized drones, and remains the classic preferred solution for drone attitude sensing and inertial navigation systems.