Huawei FreeBuds Pro 2 was officially released on July 28, 2022, ushering in a full range of upgrades. In terms of appearance, it continues the classic design of the previous generation, but the volume of the charging case is reduced by 11% and the weight is reduced by 13%, making it more portable. The streamlined earbuds effectively reduce wind noise, the headset stem is also shorter, and supports IP54 water resistance, so it is not afraid of sports sweat and rain.
In terms of functional configuration, Huawei FreeBuds Pro 2 has undergone a systematic full-link upgrade in terms of sound quality, and is equipped with the world’s first 4-magnet dynamic driver and microplanar driver released by TWS. With digital frequency division technology, L2HC and LDAC dual HD audio decoding, triple hearing optimization algorithm and many other audio technologies. Combined with Devialet tuning, it perfectly reproduces the essence of sound, and has obtained both HWA and Hi-Res certification. Spatial audio has also been added for a more immersive surround listening experience.
Huawei FreeBuds Pro 2 is also the world’s first 3-mic ANC TWS earbuds, achieving a maximum noise cancelling depth of 47dB. The newly upgraded intelligent dynamic noise cancelling 2.0 automatically switches the noise cancelling mode. At the same time, three microphone units and bone conduction microphones are used to accurately pick up sound, combined with noise cancelling algorithm and anti-wind noise structure design, to achieve a clear call effect in the whole scene. It also supports smart pop-up quick connection, full-scene multi-device connection, wireless charging, etc., with a comprehensive battery life of 30 hours.
52audio has previously teardown Huawei products including: Huawei FreeBuds 4E, Huawei FreeBuds 4, Huawei FreeBuds 4i, Huawei FreeBuds Pro, Huawei FreeBuds 3, Huawei FreeBuds 2 Pro, etc. Let’s take a look at the teardown report of this product below.
01/ HUAWEI FreeBuds Pro 2 charging case teardown
Disassemble the charging case shell and take out the internal cockpit structure.
The main board unit is fixed by screws at the bottom of the cockpit, and the components on the main board are glued and fixed.
The wireless charging receiving coil is fixed on the front of the cockpit.
The rear structure of the cockpit is arranged with indicator lights and Hall element cables.
The LED and Hall element cables are connected to the motherboard through BTB connectors.
A rubber cushion is attached to the small panel of function buttons on the side of the cockpit.
Tear off the rubber pad, and move the small key board below.
Peel off the wireless charging receiving coil, the lower structure.
The wireless charging receiving coil is set on the magnetic shielding sticker.
Pick apart the connector and remove the motherboard unit.
The circuit on one side of the charging case motherboard.
The circuit on the other side of the main board of the charging case is set with metal shrapnel for earbud charging at both ends.
Type-C charging socket, through-hole welding fixed, engraved model “J23715”.
Metal shrapnel that charges the earphones.
Female BTB connector for connecting battery cell cables.
Female BTB connector for connecting Hall element and indicator cable.
Nations N32G4FRHE MCU microcontroller. The N32G4FR series adopts a 32-bit ARM Cortex-M4 core with a maximum operating frequency of 144MHz, and supports floating-point operations and DSP instructions. Built-in cryptographic algorithm hardware acceleration engine, integrated up to 512KB encrypted Flash memory, 144KB SRAM, can be used to securely store fingerprint information. It supports mainstream semiconductor fingerprint and optical fingerprint sensors, supports up to 18-channel capacitive touch buttons, and integrates rich U(S)ART, I2C, SPI, QSPI, USB, ADC, DAC, SDIO and other general peripheral interfaces.
The crystal oscillator that provides the clock for the MCU microcontroller.
The wireless charging receiver chip of the silkscreen WP5101GC adopts the same solution as Huawei FreeBuds 4 true wireless earphones.
LED indicator for feedback of charging status.
Function button small board wiring.
Jog button for bluetooth pairing connection.
Remove the screws and remove the cavity holding the battery unit.
The bottom structure of the cockpit is equipped with two rows of 6 magnets, which are used to adsorb the charging case cover and earbuds. The middle Hall element and the indicator light board are fixed by the hot-melt column.
The bottom structure of the battery frame is sealed with a transparent cover plate.
Remove the cover, the internal structure of the cavity.
The inner side of the cover is provided with a sponge pad for protection.
Remove the battery, frame the internal structure.
The BTB connector male socket where the battery cable is connected to the motherboard.
Information on the external label of the built-in lithium battery in the charging case, product model: HB781937ECW-A, rated capacity: 580mAh, rated voltage: 3.82V, charging limit voltage: 4.4V, made in China.
Tear off the outer label, silk screen information on the inner cell, model: ATL 771934, energy: 2.23Wh, rated voltage: 3.82V, from ATL.
The circuit on one side of the battery protection board.
The circuit on the other side of the battery protection board.
Silkscreen 140 466 IC.
PTC thermistor to detect battery temperature.
The other IC covered with black hard glue could not obtain detailed information.
Remove the indicator light and Hall element cable.
Circuit on one side of the cable.
Circuit on the other side of the cable.
The hall element of the silk-screen mH1m is used to sense the magnetic field change in the state of the charging case switch cover, and then notify the charging case MCU and earbuds to pair or disconnect from the connected device. Realize the function of opening the box and pair devices automatically, and automatically disconnecting the cover when entering the case.
LED indicators are used to feedback the bluetooth pairing status of the earphones and the charging status of the earphones.
The flat cable is connected to the BTB connector male socket of the motherboard.
02/ Huawei FreeBuds Pro 2 earbuds teardown
Go to the earphones teardown section. Pry off the back cover at the heated parting line.
A plastic plate is also arranged on the inner side of the cover plate, and the LDS laser antenna is printed on it.
The internal structure of the cavity, the layout of the main board are regular, and the main IC is provided with a metal cover for protection. The internal component cables and pressure sensing cables in the front cavity are connected to the motherboard through BTB connectors.
Pick up the connector and take out the motherboard.
The internal structure of the cavity, the microphone pickup holes at both ends are designed with an anti-wind noise structure to improve the sound reception effect.
Microphone pickup hole structure, with dust net and sealing rubber ring.
The end of the cable is soldered to the metal tail plug that charges the earbud.
The circuit on the other side of the earphone motherboard, the main control chip is also protected by a metal cover.
Remove the shield, the motherboard circuit.
The circuit on the other side of the motherboard.
The MEMS microphone of the laser engraving NCB4M 1333F1 on the top of the motherboard is used for the noise cancelling function to pick up external environmental noise, from Goermicro.
The MEMS microphone of the Goermicro laser engraving NCB4M 1335EX at the bottom of the motherboard is used for voice calls and noise cancelling function pickup.
Metal shrapnel for connecting the bluetooth antenna.
Another metal shrapnel connected to the bluetooth antenna.
Female BTB connector for connecting pressure sensing sensors.
Female BTB connector for connecting the cable of components inside the front chamber.
ST LSM6DSV16BX 6-axis IMU, bone conduction two-in-one chip. The 6-axis IMU is used for spatial audio functions, bone conduction is used for noise cancelling of uplink calls, and the software can support head tracking and VAD algorithms.
Awinic AW86862 pressure sensing IC with pressure sensing signal acquisition, amplification and processing functions. Integrate 1 I2C communication module, 1 system control module, 1 power management module and 1 AFE module (including 2 analog input differential channels and multiplexers, 2-level PGA, 11-bit offset calibration DAC, 14 bit ADC and push algorithm).
The earphone main control chip adopts BES BES2700YP, which is the latest generation of ultra-low power consumption and highly integrated bluetooth audio SoC from BES. It adopts 12nm process and integrates dual-mode Bluetooth 5.3. Support BT&BLE, the main processor has built-in Arm Cortex-M55 CPU and Tensilica HiFi 4 DSP, which greatly improves the computing performance of the chip. The sensor hub subsystem has built-in STAR-MC1 MCU and BES self-developed neural network processor BECO NPU, which not only significantly reduces power consumption, but also achieves rich application processing capabilities.
According to 52audio, the true wireless earphones of many brands such as OPPO, Xiaomi, Samsung, vivo, Honor, JBL, 1MORE, Baidu, and OnePlus are widely used.
Silkscreen KZ IC.
The crystal oscillator that provides the clock for the bluetooth chip.
The BTB connector male socket at the end of the internal component cable of the earphone head.
The pressure sensor is fixed on the side cavity.
The BTB connector male socket where the pressure sensor cable is connected to the motherboard.
The pressure sensor supports pinch and slide control. According to 52audio, the pressure-sensing solution of NDT is adopted.
Melt off the solder joints and take out the cable.
Pry open the earphone head, and the internal components of the cavity are fixed by plastic parts.
The FPC board is also provided with a metal cover for protection.
The battery unit is set in the middle of the plastic part.
A microplanar driver and an in-ear noise cancelling microphone are arranged in the sound tube at the end of the cable.
The component teardown inside the earphone head.
The internal structure of the front cavity.
The internal circuit of the earphone head.
The circuit on the FPC board.
Silkscreen MU6 L2M IC.
Cellwise CW6305B is a low-power linear charging chip for wearable devices. The maximum input current limit of the chip inlet is 500mA. It supports the maximum charging current of 470mA and the minimum charging cut-off current of 1mA. When powered by a lithium battery, the quiescent current of the chip is as low as 7uA.
The CW6305B integrates the power path management function, and the current provided by the charging adapter can be dynamically distributed between the system load and the battery. For deeply discharged batteries, the system can be turned on immediately. The chip supports the I2C interface, and the charging parameters can be dynamically adjusted.
Silkscreen IC of JMW LPA.
The earphone uses a steel shell button battery inside, and a QR code is silk-screened on one side of the label.
There is some product information on the label on the side of the battery, model: HB1160ECW.
Capacity: 55mAh, Voltage: 3.82V.
The cell is also engraved with QR code information and the “3266AX1818XD095B” model.
The optical in-ear detection sensor is used to automatically pause the audio playback when the earphone is removed, and automatically resume the playback function when the earphone is worn.
In-ear microphone and microplanar driver at the end of the cable.
Laser sculpture S811 2076EY’s MEMS microphone picks up noise from the ear for active noise cancelling.
Microplanar driver side, silk screen model G23 ZAT.
The sound hole on the other side of the microplanar driver.
Four-magnet dynamic driver front diaphragm.
Four-magnet dynamic driver back.
All components of HUAWEI FreeBuds Pro 2 true wireless noise cancelling earphones.
HUAWEI FreeBuds Pro 2 continues the design style of the previous generation in terms of appearance. The approximately oval-shaped rounded square charging case is smaller and easier to carry. The handle-shaped in-ear earphones, the square headset stem is shorter, the earphone curve is smoother, and the overall design is lighter, which further improves the wearing comfort.
In terms of internal structure configuration, it is simpler than the previous generation, but it is still more complicated. The interior of the charging case mainly includes the battery, the motherboard and two FPC cables. The built-in battery is fixed in a separate cavity, which plays a good protective role. The components are connected by BTB connectors, which is convenient for assembly and production.
The charging case has a built-in ATL 580mAh lithium battery, and is equipped with a circuit protection board responsible for the lithium battery protection function. The charging case supports both wired and wireless input power. Wired charging adopts Type-C interface, and wireless charging adopts WP5101GC wireless charging receiver chip. The Nations N32G4FRHE MCU microcontroller is also used for the overall control of the charging case.
In terms of the internal circuit of the earphone, the components in the earbud head are connected to the same FPC cable, and then connected to the motherboard through the BTB connector. The components include a dual-unit, 55mAh steel-shell button battery, an in-ear noise cancelling microphone, and an optical in-ear detection sensor. The FPC cable also uses a CellWise CW6305B low-power linear charging chip to charge the built-in battery.
The headset stem includes the motherboard unit, pressure sensing sensor and bluetooth antenna. The motherboard is equipped with two Goermicro out-of-ear noise cancelling microphones to pick up external ambient noise. The main control chip is BES’s latest generation BES2700YP bluetooth audio SoC, dual-mode Bluetooth 5.3, supports BT&BLE, and has ultra-low power consumption and rich application processing capabilities. ST LSM6DSV16BX 6-axis IMU and bone conduction two-in-one chip are also used for spatial audio and call noise cancelling functions.