OnePlus Buds Pro 2 is OnePlus’ flagship TWS earbuds. The acoustic system jointly developed with Dynaudio uses newly upgraded coaxial dual drivers, and the frequency range is increased to 10-40KHz. Paired with the LHDC5.0 transmission protocol, it presents rich and delicate sound quality and has obtained Hi-Res Audio Wireless certification. At the same time, a new spatial audio function with dynamic head tracking is added, which can be used with a OnePlus mobile phone that supports Dolby Atmos to provide an immersive three-dimensional listening experience.

The maximum noise cancellation depth of OnePlus Buds Pro 2 has been upgraded to 48dB, and the noise cancellation width has been increased to 4000Hz. Supports smart dynamic noise cancellation, which can intelligently identify the noise cancellation environment and automatically switch to the best noise cancellation mode. Supports smart personalized noise cancellation and customizes noise cancellation curves based on different user ear structures. It also supports transparency mode, 3-Mic + AI call noise cancellation, and a triple anti-wind noise design to meet the noise cancellation needs in all scenarios.

OnePlus Buds Pro 2 adds cervical spine health management and focus mode. The former automatically recognizes the posture of the head and neck, which is used to remind people to lower their heads for a long time and provide neck weight bearing reports. The latter can play white noise with one click, making users more focused at work and improving work efficiency.The single battery life is 9 hours (ANC OFF), and the comprehensive battery life can reach 39 hours. It also supports Qi wireless charging and fast charging functions.

We have also teardown the OnePlus products including: OnePlus Buds Ace, OnePlus Buds N, OnePlus Buds Pro, OnePlus Buds Z2, OnePlus Buds Z, and more. Let’s take a look at the detailed teardown report of OnePlus Buds Pro 2.

01/ OnePlus Buds Pro 2 Charging Case Teardown

Disassemble the charging case and take out the charging bin.

The bottom structure of the charging bin is equipped with an FPC for charging earbuds, and 8 magnets for adsorbing and fixing earbuds and charging case lid.

The internal structure of the cavity is equipped with a motherboard, a small power input board, a battery and a wireless charging receiving coil. The FPC that charges the earbuds is connected to the motherboard through a ZIF connector.

Unhook the connector and remove the FPC.

FPC circuit for charging earbuds.

Remove the fixing screws and take out all the components inside the cavity.

The wireless charging receiving coil is set on the magnetic shielding sticker.

The motherboard is fixed with brackets.

There is a battery on the other side of the bracket.

The power input is on the small board circuit, and the FPC is welded to the main board. The Type-C charging interface is protected by an insulating rubber cover.

Remove the motherboard and battery from the stand.

The circuit on the side of the charging case motherboard.

The circuit on the other side of the charging case motherboard.

TPS SY8809 bluetooth headset charging bin solution. The chip integrates a charging module and a discharging module. The charging module adopts NVDC architecture, and the battery-side charging current can be adjusted by I2C. The output voltage of the discharge module can be adjusted by I2C and integrates two output current-limiting switches to provide independent load presence detection and load insertion detection – while supporting output current detection. The chip integrates NTC protection function to charge and discharge the battery more safely.

SY8809 integrates a standard I2C interface and interrupt signal to facilitate communication between the chip and MCU and control the charging/discharging function. SY8809 integrates a communication port, which can realize high-speed communication from the MCU to the headset, and is very suitable for the design of charging bin. The high level of integration greatly simplifies peripheral circuits and components, providing a simple and easy-to-use solution for charging bin applications. The package format used by SY8809 is QFN4x4-24.

Power management chip peripheral inductor.

Silk screen UTG IC.

Silk screen 8891P IC.

WillSemi ESD56241D TVS protection tube. The ESD56241DXX series is a transient voltage suppressor designed to protect power interfaces – with high surge capabilities suitable for replacement of multiple discrete components in portable electronic equipment. Available in DFN2x2-3L package, standard products are lead-free and halogen-free.

Silk screen 3412 WQ IC.

LPS LP5308 overvoltage and overcurrent protection IC has a voltage resistance of up to 36V and can absorb instantaneous voltage spikes. The internal resistance of 135mΩ makes the voltage loss at the input terminal smaller and adopts a safer positive protection method. At the same time, the response time of the input overvoltage protection is extremely short at 40ns, which can effectively prevent instantaneous plugging and unplugging spikes.

Silk screen 5225J2SZ lithium battery integrated protection chip.

NuVolta NU1680 is a small-sized, highly integrated wireless power receiver. A synchronous rectifier is integrated internally, eliminating the need for external bootstrap capacitors, and is characterized by high efficiency and low cost. It can provide a wide range of regulated voltage from 3.5V to 9V, suitable for different applications. The output voltage can be adjusted to track the battery voltage and reduce the power consumption of the charging system.

NU1680 can communicate with the transmitting system through ASK, and the communication complies with WPC V1.2.4. FOD parameters are configurable through the I2C interface or external resistors. Supports I2C interface for communication. Provides external interrupts, battery voltage ADC value, output current, etc. NU1680 also supports standard protection functions such as over-current protection, short-circuit protection, over-voltage protection and thermal shutdown.

Chipsea CS32F035 microcontroller uses a high-performance 32-bit ARM Cortex-M0 core, embedded with up to 32Kbytes flash and 4Kbytes SRAM, and has a maximum operating frequency of 48MHz. The CS32F035/F036 series covers a variety of products from 20 pins to 32 pins. The chip provides standard communication interfaces (I2C, SPI and USART), 1 12-bit ADC, 5 16-bit timers, and 1 enhanced control PWM timer. The operating temperature range is -40℃~85/105℃, and the operating voltage range is 2V~5.5V.

Function button for bluetooth pairing.

Pogo Pin connector for charging earbuds.

Charging case has built-in rechargeable lithium-ion battery, model: 631940, rated capacity: 520mA 1.976Wh, typical capacity: 525mAh 1.995Wh, charging limit voltage: 4.35V, nominal voltage: 3.80V, manufacturer: Chongqing VDL Electronics Co., Ltd.

Tear off the outer insulation protection, and the information on the inner battery core is consistent with the outer label.

02/ OnePlus Buds Pro 2 Earbuds Teardown

Remove the earbud tail plug and disassemble the earbud head cavity.

The internal structure of the front cavity holds the battery and FPC through brackets. The middle one is the BTB connector that connects the FPC to the motherboard, from OCN, model: OK-114GFO12-35.

WINSEMI WSDF23C2N2H lithium battery protection IC, belonging to the WSDF23 series, is a highly integrated solution for single-cell lithium-ion/lithium polymer rechargeable battery pack protection. It adopts DFN4L-1X1 ultra-small package, built-in advanced power MOSFET, high-precision voltage detection circuit and delay circuit – it has all the protection functions required by the battery such as overcharge, over-discharge, over-current, short circuit, etc. And the power consumption is very low when working, and it also has CTL shipping mode setting function.

The internal structure of the rear cavity, you can see the motherboard inside the earbud stem.

Pull out the components inside the earbud stem.

The front structure of the earbud motherboard is fixed on the bracket.

There is a microphone pickup hole on the back of the stand and an LDS bluetooth antenna is printed on it.

Remove the motherboard from the stand. The FPC of the pressure sensor sensor and call microphone are also fixed on the inside of the bracket.

The MEMS microphone of Laser Engraving SAB3 is a call microphone, which is used to pick up human voices during the call function.

The BTB connector that connects the FPC to the motherboard is from OCN, model: OK-114GM008-35.

The circuit on one side of the earbud motherboard.

The circuit on the other side of the earbud motherboard.

The BTB connector that connects the FPC internal components of the earbud head is from OCN, model number: OK-114GM012-35.

Silk screen 2111 K001 IC.

TPS SY5501 power management PMIC is a chip specially designed for TWS earbuds, providing a perfect solution for charging and isolated communication. The chip integrates linear charging management, discharge protection, single-line two-way data communication and I2C communication interface to facilitate users to realize headset charge and discharge management and protocol communication.

The maximum charging current of SY5501 is adjustable by an external resistor, and it also supports constant current charging ICC and float charging voltage VFLOAT gear I2C adjustment. The chip integrates NTC detection and protection functions to manage battery charge and discharge more safely. SY5501 has battery discharge protection and shipmode functions, which can meet the low power consumption requirements of the headset system. The chip integrates private control instructions, and the charging bin can send instructions through VIN to control the SY5501 to realize the power on and reset operations of the headphone main control.

A 24.000MHz crystal oscillator is used to provide the clock.

The MEMS microphone of Lasdiao S5B31 is a feed-forward noise cancellation microphone, used to pick up external environmental noise.

Silk screen I467P 6-axis gyroscope, model: ICM-42670-P, from TDK, used for spatial audio function to collect user head movement data.

Metal dome for connecting bluetooth antenna.

Silk screen AHCP IC.

BES BES2600YP bluetooth audio SoC, bluetooth + noise cancellation + in-ear detection 3-in-1 single chip solution. Supports dual-mode Bluetooth 5.3 and multipoint connections. Internally integrated dual-core ARM STAR-MC1 CPU and ultra-low power Sensor Hub subsystem have powerful application processing capabilities. Supports open adaptive noise cancellation and AI noise cancellation. Supports assistive listening function and spatial audio. Support voice wake-up and interactive functions.

The BTB connector that connects the pressure sensor sensor and the call microphone cable is from OCN, model: OK-114GF008-35.

Take out the battery and FPC inside the front cavity of the headset.

The earbuds have a built-in soft-pack button battery, model number: 122540, nominal voltage: 3.85V, energy: 0.231Wh.

The bottom structure of the front cavity has a capacitive in-ear detection sensor attached to the cavity wall, and is equipped with a charging connector and two magnets.

Take out the speaker and FPC.

The front of the coaxial dual driver adopts a high and bass dual unit design. Arranged in a coaxial form, the crossover points are perfectly integrated, and the frequency range reaches 10-40KHz, which can present rich and delicate sound quality.

After actual measurement, the diameter of the woofer unit is approximately 11mm.

Charging connector on FPC.

The MEMS microphone of the laser-engraved S5B31 at the end of the FPC is a feed-back noise cancellation microphone, used to pick up noise from inside the ear canal.

All components of OnePlus Buds Pro 2 true wireless noise cancellation earphones.

03/ Summary

OnePlus Buds Pro 2 continues the classic design of the previous model – the square charging case is compact and the NCL matte coating is smooth and comfortable to the touch. The long-stem in-ear earbuds use a combination of NCL matte coating and polished indium raw materials, which are highly textured and recognizable.

The charging case is equipped with a 520mAh lithium battery and supports wired and wireless charging modes. Wired charging adopts TPS SY8809 charging bin solution – integrated charging module, discharge module and NTC protection function. Integrate standard I2C interface and interrupt signal to facilitate communication between chip and MCU – control charging and discharging functions.

The wireless charging uses the NuVolta NU1680 wireless power receiver, which provides a wide range of regulated voltage from 3.5V to 9V and complies with the WPC V1.2.4 specification. The charging case control is handled by Chipsea CS32F035 microcontroller. It also uses LPS LP5308 overvoltage and overcurrent protection IC, WillSemi ESD56241D TVS protection tube, etc.

The earbud is equipped with a 0.231Wh soft-pack button battery – the TPS SY5501 power management PMIC is used for charging and isolation communication, and the WINSEMI WSDF23C2N2H lithium battery protection IC is used for charge and discharge protection. A single earbud has three built-in MEMS microphones to pick up sound, and the main control chip is BES BES2600YP bluetooth audio SoC. A TDK ICM-42670-P 6-axis gyroscope is also used for the spatial audio function to collect movement data of the user’s head.

PS: Translated from 52audio

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