DJI Mini 2 Drone Simple Teardown and Analysis
I bought my DJI Mini 2 drone four years ago, and recently found that its 5.8GHz wireless video transmission signal had become extremely weak. After searching online, this issue appears to be a common problem with the 5.8G wireless power amplifier chip. Since it was out of warranty, I decided to try replacing it myself.
Note: Some chip information interpretations in the article include AI-generated content!
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Teardown
Unscrew the cross screws around the bottom of the drone.
Remove the battery, then pry open the outer shell clips on both sides inside the battery compartment.
You can now remove the upper cover of the case. The ceramic antenna for GPS is directly in the center.
The circuit board below the GPS antenna is the three-phase sensorless BLDC (brushless DC motor) driver board. The chip in the middle of the board is labeled SPC1168APE48 from SPINTROL, a highly integrated SoC microcontroller, likely used for motor control, driving the surrounding MOSFETs to control the motors.
The SPC1168 integrates a high-performance 32-bit ARM Cortex-M4 core, up to 200MHz software-programmable clock, 64KB SRAM, 128KB embedded FLASH, and a wealth of enhanced I/O and peripheral resources. Built-in 14-bit ADC, three programmable gain op-amps, six enhanced PWM modules, three general-purpose 32-bit timers, along with UART, I2C, SPI, etc. communication interfaces, making it an ideal platform for motor control. In addition, it adopts two innovative technologies: a multi-zone safety protection technology for code security and a flexible IO technology similar to FPGA, enabling IOs to be configured as different peripherals for diverse application needs, but with a more cost-effective approach.
Around the motor driver board are four groups of MOSFET chips (three per group), corresponding to the motors for the four rotors. The MOSFET model is AON7934 from Alpha and Omega Semiconductor (AOS), a dual N-channel MOSFET with two NMOS in a single chip forming a half-bridge.
Key Chip Parameters:
- Electrical Performance:
- Drain-source voltage (Vds): 30V
- Continuous drain current (Id): 16A/18A (different channels)
- On-resistance (Rds (on)): minimum 10.2 mΩ @ 16A, 10V
- Input capacitance (Ciss): 485pF
- Packaging and Reliability: DFN-8(3x3) package, supports -55℃~150℃ wide-temperature operation, meeting the reliability requirements for drones in harsh outdoor environments.
Above the battery interface is an AON6407 chip, also from AOS, a P-channel power MOSFET.
Key Parameters and Features:
- Electrical Performance: Drain-source voltage (Vds) -30V, continuous drain current (Id) -85A, on-resistance (Rds (on)) 4.5mΩ
- Packaging: PDFN-8(5.8x4.9)
Function Analysis:
This AON6407 chip serves as the power control switch on the battery power line above the battery connector and undertakes several key functions:
- Power On/Off Control: Controls the power transfer between the battery and the drone’s main circuit, enabling precise on/off switching.
- Efficient Power Transmission: With a low on-resistance (4.5mΩ), it reduces power loss during battery supply and improves energy efficiency, indirectly extending drone battery life.
- Circuit Protection: Can quickly cut off the circuit in case of overcurrent or overvoltage, preventing damage to the battery or backend systems and ensuring power system reliability.
In short, it’s the power “gatekeeper” between the battery and the drone’s core circuits, ensuring efficient power transfer and acting as a safety buffer for the power system.
On the back of the motor driver board are four MP6530 chips from MPS (Monolithic Power Systems), which are gate driver ICs specifically designed for three-phase brushless DC motors. They can drive three half-bridges made up of six N-channel MOSFETs and handle up to 60V.
Unscrew the two cross screws under the battery compartment to remove the bottom cover of the drone.
The first thing visible is a large black aluminum alloy heatsink, with a downward-facing camera and infrared range-finding module beneath it.
After removing the heatsink, the shield can and some chips are coated with blue thermal silicone.
Remove the motherboard just mentioned—on the back, you’ll find the Type-C charging port and TF card slot on this board.
Lift the shield under the TF card slot (the other side of the board is where the downward camera module sits) and you’ll find a OPT3101 chip from Texas Instruments (TI).
Core Attributes & Functions:
- Technology: Based on Time-of-Flight (ToF) principles, a long-distance proximity and ranging sensor analog front end (AFE).
- Key Specifications:
- Ranging distance: up to 15 meters without ambiguity, supports 16-bit distance output and 3mm resolution.
- Ambient Light Resilience: Excellent sunlight rejection, operates in full sunlight up to 130klx.
- Integration: Built-in ADC, timing sequencer, digital processing engine, and emitter driver, supporting 3 transmitter channels.
Role in the Device:
As the ToF sensor core, it provides:
- Precise Ranging: Real-time distance measurement for drones and other devices, aiding in flight control and obstacle avoidance.
- Environmental Awareness: Identifies the location and distance of nearby obstacles via multi-zone sensing, enhancing smart interaction and safety.
- Anti-Interference Operation: Not affected by object reflectivity; can output stable depth data even in complex lighting environments.
A shield in the middle contains a muRata chip, model SS1029009, suspected to handle video transmission signal modulation/demodulation.
The largest shield encloses three main chips: MIMXRT1064, TC58NVG1S3H, and NT5CB128M16JR-FL.
1. i.MX RT1064 (MIMXRT1064)
- Brand & Positioning: NXP’s high-performance crossover processor, part of the i.MX RT series.
- Key Specs:
- Core: Cortex-M7, up to 600MHz
- Storage: Supports external DDR and Flash, high-speed data processing
- Function: Acts as the main controller for the Mini 2, handling flight control, sensor data fusion, and image pre-processing. It’s basically the “brain” of the drone.
2. TC58NVG1S3H (Toshiba Flash Memory)
- Brand & Positioning: SLC NAND flash from Toshiba
- Key Specs:
- Capacity: 2Gbit (256MByte), industrial-grade
- Features: Supports high-speed read/write, data protection on power loss
- Function: Stores the drone’s firmware, flight logs, calibration parameters, and other key data to ensure system stability.
3. NT5CB128M16JR-FL (Nanya DDR RAM)
- Brand & Positioning: DDR3 RAM from Nanya
- Key Specs:
- Capacity: 128M×16bit (2Gbit = 256MByte), 1.5V operating voltage
- Data rate: Up to 2133 MT/s (DDR3-2133), corresponding to a 1066 MHz clock
- Performance: Supports high data throughput for main chip bandwidth needs
- Function: As working memory, provides data cache for the i.MX RT1064, ensuring smooth operation for flight algorithms and real-time image processing.
Below the downward camera module, inside its shield, are three main chips: S1 V10R03, 4205, and 4550.
1. S1 V10R03 Chip
- Type: Custom video transmission communication chip (DJI OcuSync system’s S1 series, codename “Sparrow 1”)
- Function: Serves as the drone’s video transmission core, taking care of wireless signal modulation/demodulation, data transfer, and encryption—key to achieving low latency, stable video transmission. It specifically manages the RF communication, with video encoding handled by other chips; in the Mini series, it basically acts as a “modem.”
- Specs: Up to 20MHz bandwidth, custom architecture, optimized for DJI’s wireless protocols, exclusive to DJI products—one of its technology “moats.”
2. 4205 Chip
- Type: 2.4GHz RF power amplifier (speculated to be from the QPF4206 series; silkscreen may be abbreviated)
- Function: Amplifies 2.4GHz wireless signals to enhance range and anti-interference on this band. The Mini 2 uses the 2.4GHz band for long-distance comms, especially in open environments; this chip is key for high performance in that spectrum.
- Specs: Operates at 2.4GHz, provides high-efficiency signal amplification within regulatory limits while reducing power consumption to suit endurance needs.
3. 4550 Chip
- Type: 5.8GHz RF power amplifier (model QPF4550)
- Function: Amplifies 5.8GHz wireless signals, a band with wider bandwidth, suitable for HD video but with weaker penetration. This chip enhances 5.8GHz signal strength, ensuring stable HD transmission for the Mini 2 at short distance and in low-interference environments (like low-latency city filming).
- Specs: Optimized for 5.8GHz, high power efficiency, maintains signal quality during high-bandwidth transfers; it’s core to the Mini 2’s “low-latency video” hardware.
These three chips work together as the Mini 2’s wireless comms backbone: S1 handles “encoding and transmission management,” while 4205 and 4550 respectively boost the 2.4GHz and 5.8GHz signal strength, enabling long-range, low-latency video feeds.
In the shield next to the aerial camera connector are two main chips: H22-AO-RH and NT5CB128M16JR-FL.
1. Ambarella H22-A0-RH (Video Processing Chip)
Brand & Positioning: Ambarella is a leading provider of video processors. The H22 series is a high-performance vision processing solution for consumer drones.
Key Architecture/Process:
- CPU: Quad-core ARM Cortex-A53 up to 1 GHz, supporting multitasking and general computation.
- Manufacturing: 14nm for a balance of performance and efficiency, suited for portable devices.
- GPU: No clear standalone GPU, but includes high-performance video DSP, supports 4K video encoding/decoding.
Video Processing Ability:
- Codec: H.265 (HEVC) and H.264 (AVC), supports dual video streams (e.g., 4K60fps main stream + mobile preview stream).
Resolution & Frame Rate:
- Main stream: 4K@60fps (HEVC/AVC)
- Substream: Real-time mobile preview (e.g., 1080p) WiFi live
Image Enhancement:
- 3D EIS: 4K30fps
- Multi-exposure HDR: 4K30fps
- Lens distortion/shutter correction
2. Nanya NT5CB128M16JR-FL (DDR RAM Chip)
- Brand & Positioning: DDR3 RAM by Nanya
- Key Specs:
- Capacity: 128M×16bit (2Gbit = 256MByte), 1.5V
- Performance: Fast data throughput for Ambarella H22’s video buffer and algorithm needs
- Function: Working memory for the video processor, guaranteeing smooth 4K video encoding and real-time image handling.
These two chips together form the drone’s visual processing core unit: the Ambarella H22 handles HD video and smart algorithms, while the Nanya RAM works as the “temporary warehouse”—they enable DJI drones’ 4K HD video transmission and smart vision features.
To the right of the Type-C port is a relatively large chip labeled SMB2352.
The SMB2352 is a high-performance Buck-Boost charging management IC from Qualcomm, mainly for two-series battery applications such as power banks, drones, and portable computers. Main specs include:
- Input: 3.3V~16.5V (supports USB Type-C)
- Output: Buck-Boost adjustable, 3.3V~20V system power
- Max charge current: Up to 6A (programmable)
- Max input current: 5A (programmable)
- Input power: Up to 45W
- Efficiency: Typically over 90%
- Package: MQFN-57, 5.5mm × 5.5mm × 0.6mm
- Communication & Control: I²C interface for programmable charging settings and protections
- Protections: Input OVP, OCP, battery OTP
- Protocol support:
- USB BC 1.2
- Qualcomm Quick Charge 2.0/3.0/4.0
- USB Power Delivery (PD) 3.0 (with PD PHY)
- Type-C 1.3 compliance
The chip suits high-power-density, high-efficiency portable charging solutions, with operating mode flexibly adjustable via external controller.
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English Version of the Article: https://blog.zeruns.top/archives/75.html
