Bose QuietComfort Ultra continues the brand’s characteristic design style and is equipped with Bose immersive spatial audio technology – supporting “static” and “dynamic” listening modes to provide a more immersive sound experience. It supports smart in-ear sound field adjustment technology, which can optimize the in-ear sound field in real time according to different ear canal structures, adjust the sound and ANC technology, and customize exclusive sound effects.

Bose QuietComfort Ultra earbuds supports Snapdragon Sound technology, which provides lossless music listening, ultra-low latency gaming experience, and stable wireless connections. The earbuds have 8 built-in noise cancelling call microphones, which can accurately pick up human voices, filter out environmental noise, and provide pure and clear call effects. The single battery life is up to 6 hours, and the total battery life is about 24 hours. It supports fast charging and can be used for 2 hours after 20 minutes of charging.

We have disassembled BOSE products including: BOSE QuietComfort Earbuds II, Bose QuietComfort Earbuds, Bose Sport Earbuds, BOSE SOUNDSPORT FREE, Bose QuietComfort Ultra Headphones, BOSE QuietComfort 45, Bose NC700 and Bose QuietComfort 35 II. Let’s take a look at the detailed teardown report of Bose QuietComfort Ultra earbuds.

01/ Bose QuietComfort Ultra Charging Case Teardown

Pry open the charging case and remove the lid.

Take out the charging bin. The charging bin has an FPC connected to the motherboard inside the cavity.

Separate the FPC and charge the bin side structure.

The LED indicator light on the FPC is used to feedback the charging case charging and bluetooth pairing status.

Open the black foam covering the FPC, and there is an indicator light and Hall element underneath. The silk-printed 2DU Hall element is used to sense the magnetic field changes when the charging case lid is opened/closed, notify the charging case control chip, and then notify the earbuds to connect/disconnect from the paired device.

LED indicators and light guides used to feedback earbuds charging status.

Indicator light guide pillar on the cavity wall.

The internal structure of the charging case cavity holds the motherboard and battery through a bracket.

Remove the screws and take out the internal components of the cavity.

The structure on one side of the bracket secures the battery.

The structure on the other side of the bracket secures the motherboard with screws.

The battery wires are soldered to the motherboard.

After removing the wires and screws, remove the motherboard.

Thermistor FPC used to detect battery temperature.

The charging case has a built-in cylindrical lithium battery, model: NTA3663, nominal voltage: 3.8V, rated capacity: 1100mAh 4.18Wh, charging limit voltage: 4.3V, from Shenzhen GP Rechargeable Li-Ion Battery Co., Ltd., made in China.

Battery protection board circuit, main IC is protected by black hard glue.

The circuit on the side of the charging case motherboard.

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

Silk screen KI resettable fuse.

Function button for bluetooth pairing.

ST STM32U575 ultra-low power MCU uses Arm Cortex-M33 processor core. Built-in DSP and floating point unit (FPU) for charging case control.

TI TLV9002 dual-channel operational amplifier with rail-to-rail input and output swing capabilities. These op amps provide cost-effective solutions for space-constrained applications that require low operating voltages and high capacitive load drivers (smoke detectors, wearable electronics, and small appliances). The TLV900x series’ capacitive load drivers feature 500pF of capacitance, and the resistive open-loop output impedance enables easier stabilization with higher capacitive loads.

TI TPS25200 5V electronic fuse with high-precision adjustable current limit and overvoltage clamping. It can withstand an input voltage of 20V and has an internal power switch of 60mΩ, which can be used to protect the power supply, device and load under a variety of abnormal conditions.

Silk screen 6EM step-down IC is used to power the MCU chip inside the charging case.

TI BQ25618 charging IC integrates switching charging, synchronous boost converter and voltage protection functions. It supports 22V withstand voltage and can reduce battery leakage to 6uA in transport mode, which is used to charge lithium batteries and earbuds.

Silk screen M14 IC and K64 3DU IC.

Silk screen 37PI IC is used to boost the charging case battery to charge the earbuds.

02/ Bose QuietComfort Ultra Earbuds Teardown

Remove the back cover of the earbud stem, and there is a cover underneath with printed touch detection electrodes and LDS laser antenna.

The internal structure of the earbud stem cavity, the motherboard connects two FPCs through BTB connectors, and is glued to strengthen the fixation.

Unhook the connector.

Disassemble the earbud head cavity.

The positive and negative terminals of the battery are connected to the motherboard.

Disconnect the wires and separate the front cavity structure.

The magnets fixed on the cavity wall are used to adsorb and fix the charging case.

Connect the noise cancelling microphone to the FPC on the other side. Laser-engraved 322o BUM MEMS microphone is used for the noise cancelling function to pick up external environmental noise.

The battery structure inside the front cavity is fixed by a bracket and isolated from the sound cavity.

The NTC attached to the battery surface monitors the battery temperature.

Take out the internal motherboard of the earbud stem.

There are also charging contacts and a small microphone board under the motherboard. The power input board is welded to the charging contacts.

The laser-engraved 322o BUM MEMS microphone is a call microphone, used for voice call function pickup.

The circuit on one side of the earbud motherboard.

The circuit on the other side of the earbud motherboard.

Qualcomm QCC5181 bluetooth audio SoC is part of the second-generation Qualcomm S5 audio platform. Supports Bluetooth 5.4 and is fully compliant with Bluetooth LE Audio (Low Energy Audio) support – including Auracast broadcast audio. Supports Snapdragon Sound technology and brings new features to it – including dynamic head-tracking spatial audio, 48kHz lossless music streaming and 48ms low-latency gaming experience.

Snapdragon Sound supports Qualcomm aptX audio codec technology, including aptX Adaptive adaptive audio, up to 24bit/96KHz. Supports aptX Voice ultra-wideband voice technology, eighth-generation Qualcomm cVc echo cancellation and noise suppression technology. Integrated Qualcomm adaptive active noise canceling (ANC) technology, including feedforward, feedback, hybrid and adaptive, supports third-party innovation through Qualcomm extensions.

Silk screen 73 Qf low pass filter.

Silk screen VL 108 gyroscope IC, used for spatial audio function to collect head movement data.

Silk screen 12 32305 IC.

Silk screen 6EM step-down IC. Silk screen 129 Y2B and 33206 IC.

ST STM32U585 ultra-low power microcontroller for sound tuning and optimization functions.

Infineon PSoC 4000S series MCU, silk screen model number “CY8C4025FNI-S412”, used for touch detection function. PSoC 4 is a scalable and reconfigurable platform architecture for a family of programmable embedded system controllers based on Arm Cortex-M0+CPU. It integrates programmable and reconfigurable analog and digital modules with the ability to flexibly and automatically route resources.

The PSOC 4000S product family is a member of the PSOC 4 platform architecture. The product family integrates microcontrollers with standard communications and timing peripherals, a best-in-class performance capacitive touch sensing (CapSense) system, programmable general-purpose, continuous and switched-capacitor analog blocks, and programmable interfaces. In response to new application and design requirements, PSOC 4000S products are upwardly compatible with the PSOC 4 platform series products.

Silk screen C 2EX IC and silk screen 71215 BCBZ noise canceling IC, from ADI, customized by BOSE.

Remove the battery. The battery is glued to the sound chamber baffle using dot glue.

The earbuds uses a steel shell button battery, model: M1454S2, voltage: 3.85V, capacity: 0.404Wh.

The front cavity cover structure is designed with an inverter tube, which is connected to the external tuning hole of the earbuds to improve the low-frequency quantity of the earbuds.

The internal structure of the front cavity connects the speakers, microphones and in-ear detection sensors through FPC.

Laser-engraved 322o BUM MEMS microphone, used for voice calls and noise cancelling function pickup.

Remove all components inside the front cavity.

The optical in-ear detection sensor has a window opening and a light hood to improve detection accuracy.

The circuitry on the component side of the front cavity interior. The earbud speaker is equipped with a layer of fiber diaphragm to improve the bass effect.

The circuit on the other side of the internal components of the front cavity.

A laser-engraved 216 WBJ26 in-ear microphone is used for intelligent in-ear sound field adjustment and noise cancelling function pickup.

Infrared distance sensor is used to automatically resume playback when wearing headphones and automatically pause playback when taking them off.

After actual measurement, the speaker diameter is approximately 9.21mm.

All components of Bose QuietComfort Ultra wireless noise canceling earbuds.

03/ Summary

The Bose QuietComfort Ultra continues the design of the previous model. The charging case has a matte texture and is lightweight and portable. The earbuds adopt a short-stem in-ear design, and the back cover is treated with a metal coating, bringing excellent texture and recognition. The earbuds are equipped with soft eartips and fixed rings of various sizes, which can provide a comfortable and stable wearing experience for different users.

The charging case has a built-in 1100mAh cylindrical lithium battery and is equipped with a circuit protection board for charge and discharge protection. The motherboard uses TI BQ25618 charging IC, ST STM32U575 ultra-low power MCU, TI TLV9002 dual-channel operational amplifier and TI TPS25200 electronic fuse, etc.

The earbud is equipped with a 0.404Wh steel shell button battery and uses a 9.21mm dynamic driver. A single earbud has 4 built-in MEMS microphones, providing all-round accurate sound pickup. The motherboard is equipped with the second-generation Qualcomm S5 audio platform (QCC5181), ADI noise canceling IC, ST STM32U585 ultra-low power microcontroller, Infineon PSoC 4000S series MCU, and a gyroscope IC, etc.

PS: Translated from 52audio

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