In the TWS earbuds market, Nothing has launched its first product in 2021 – Nothing Ear (1). Recently, the second product – Nothing Ear (Stick) was officially released. It adopts the semi-in-ear design and complements the product line.

The appearance of Nothing ear (stick) continues the family-style design of transparent elements. The charging case is inspired by lipstick, and the earbuds adopt a more comfortable semi-in-ear design, which is light in size and comfortable to wear. In terms of functional configuration, it is equipped with a customized 12.6mm dynamic driver, which supports dynamic bass adjustment. Built-in three microphone units, support a new generation of clear voice technology. With Nothing Phone (1), it can automatically switch to low-latency mode.

In other respects, the Nothing ear (stick) supports wearing detection, and the pressure-sensitive buttons have been upgraded to achieve more precise operation control. Equipped with Nothing X APP, you can customize pressure-sensitive control, EQ settings, etc. In terms of battery life, the earbuds play for up to 7 hours at a time, and the combined battery life when used with a charging case reaches 22 hours. Let’s take a look at the detailed teardown report of this product.

01/ Nothing Ear (Stick) charging case teardown

Remove the rotating structure on the charging case.

A small power input board is set inside the structure, which is fixed by screws.

The upper structure of the main body is equipped with a metal shaft to realize the rotation function. The wires inside the cavity are connected to the power input small board through the socket connector.

Remove the cover from the other end of the charging case. Fixing screws are arranged under the cover plate.

Remove the screws and take off the transparent case.

The metal shaft structure at one end of the charging case.

The internal structure after opening the cylindrical charging case cockpit cavity.

The internal structure of the charging case cockpit, the main board is fixed by screws. The battery is attached to the motherboard and covered with a sponge pad for protection.

The main board structure and the hollow structure cleverly fit the cavity, maximizing the use of internal space.

Take off the main board, set the small board for earbuds charging independently, and connect to the main board through a cable and a connector.

Nothing ear (stick) charging case teardown, including motherboard, battery and cable for earbuds charging.

The inner structure of the charging case cockpit, as well as magnets and indicator light guide columns.

The charging case built-in lithium battery model: 391357PN4, rated voltage: 3.85V, capacity: 350mAh/1.347Wh. Adapt to the elongated design of the cavity to provide greater capacity.

The front circuit of the battery protection board is equipped with an integrated lithium battery protection IC and a thermistor for monitoring the battery temperature.

An integrated lithium battery protection IC with silk screen “1GBK”.

The circuit on the wiring side.

Two LED indicators of different colors.

Pogo Pin connector for charging earbuds.

Circuits on the motherboard side.

Circuits on the other side of the motherboard.

The ZIF connector that connects to the flex cable that charges the earbuds.

TPS SY8809 bluetooth earphones charging compartment solution, the chip integrates a charging module and a discharging module, the charging module adopts NVDC architecture, and the charging current of the battery terminal can be adjusted by I2C. The discharge module output voltage I2C can be adjusted, and integrates two output current-limiting switches, which provides independent load presence detection and load insertion detection, and supports output current detection. The chip integrates NTC protection function to charge and discharge the battery more safely. SY8809 integrates standard I2C interface and interrupt signal, which facilitates the communication between the chip and MCU, and controls the charging and discharging functions. the

Magnetic glue power inductor around the power management chip.

Chipsea CS32F035 microcontroller uses a high-performance 32-bit ARM®Cortex®-M0 core, embedded 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 channel 12bit ADC, 5 16bit timers, 1 enhanced control PWM timer. The working temperature range is -40℃~85/105℃, and the working voltage range is 2V~5.5V.

TPS SY5320 overvoltage and overcurrent protection IC is a highly integrated protection IC with input undervoltage and overvoltage protection, lithium battery front-end overvoltage protection, abnormal load current protection, and overtemperature protection. Support 28V input withstand voltage, overvoltage shutdown protection is less than 1uS, support high-precision battery overvoltage protection function.

The Hall element of silk-screened AR201 is used to sense the magnetic field change when the charging case cover is turned on/off, and then inform the charging case MCU to control the pairing or disconnection of the earbuds with the connected device.

The wire socket connected with the power input small board.

The cavity of the power input board is teardown.

The power input circuit on one side of the small board.

The power input circuit on one side of the small board.

Screen-printed 23P TVS tube to prevent electrostatic breakdown of the device.

TVS with silkscreen P24 004.

The metal shrapnel connected to the function button board.

The front circuit of the function button small board is equipped with a micro button for bluetooth pairing.

02/ Nothing Ear (Stick) earbuds teardown

Go to the earbuds teardown section and remove the double layer cover on the back of the headset stem.

The internal structure of the earphone cavity, the motherboard fits the cavity design. The side pressure-sensitive key board and the internal component cables of the earphone head are connected to the main board through the BTB connector.

The back structure of the cover plate, the bluetooth antenna is fixed on the cover plate, and the exposed copper is connected to the main board.

Earphone motherboard side circuit.

The circuit on the other side of the earphone motherboard.

The laser carving 2238 8X01 MEMS microphone is used to pick up the sound of the call noise reduction function, from XINGANG.

BES BES2500YA ultra low power bluetooth audio SoC. Support dual-mode Bluetooth 5.2, built-in dual-core ARM Cortex-M33 Star cpu, integrated 4MB/8MB flash. It supports open adaptive noise reduction and AI voice, has powerful application processing capabilities, and effectively improves the single battery life of earbuds.

The 26.000MHz crystal oscillator provides the clock for the bluetooth chip.

AWINIC AW86862 pressure sensing IC, with pressure sensing signal acquisition, amplification and processing functions. Integrates 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-stage PGA, 11-bit offset calibration DAC, 14 bit ADC and intelligent pressing logic processing module). The size of AW86862 is as small as 1.41mm×1.41mm, which is 67% smaller than that of the previous generation, which is very suitable for the small space of TWS.

According to 52audio, Huawei, Xiaomi, OPPO, Honor, Lenovo, OnePlus, JBL and many other brands have adopted AWINIC chips.

Screen printing GS IC.

BTB connector female socket for connecting the internal components of the earphone head.

TPS SY5501 power management PMIC is a chip specially designed for TWS earbuds, providing a perfect solution for charging and isolation communication. The chip integrates linear charging management, discharge protection, single-wire two-way data communication and I2C communication interface, which is convenient for users to realize earphone charging and discharging management and protocol communication. The maximum charging current of SY5501 can be adjusted by an external resistor, and it also supports constant current charging ICC and floating charging voltage VFLOAT gear I2C adjustment. The chip integrates NTC detection and protection functions to more safely charge and discharge the battery.

Metal shrapnel for connecting the bluetooth antenna.

The BTB connector female seat used to connect the pressure-sensitive key board.

The laser carving 2237 8X04 MEMS microphone is used for voice pickup, also from XINGANG.

The internal structure of the earphone cavity after taking out the motherboard.

A pressure-sensitive button sensor plate fixed on the inner wall of the side cavity.

The pressure sensing sensor is used to collect data when the user operates the control.

The BTB connector male seat that connects the pressure-sensitive key board to the main board.

The circuit on the back of the cable is equipped with two metal contact connectors for earphone charging.

Pry open the earphone head cavity along the parting line.

The internal structure of the rear cavity of the earphone head is provided with a battery unit, which is fixed by a bracket.

The internal structure of the front cavity of the earphone head, the cable connected to the motherboard is connected to the speaker cable through BTB.

Take out the speaker unit, and connect the in-ear detection sensor and noise-canceling microphone to the end of the cable.

The speaker uses a dynamic driver, a high-quality speaker magnet and a special diaphragm design to increase power and sensitivity and bring a clearer and more realistic original sound experience.

After actual measurement, the size of the speaker is about 12.85mm, and the official data is 12.6mm, which is within a reasonable test error range.

The laser carving 2236 8X07 MEMS microphone is used to pick up the sound inside the ear canal to improve the noise reduction effect of the call.

Take out the battery unit inside the rear cavity, the internal structure of the cavity.

The in-ear detection sensor fixed on the back cavity wall, the silk screen model “ZHMC850027G0”, two sensors to achieve more accurate detection.

The earphone is equipped with MBT CTSS lithium-ion battery, model: MC1042D, voltage: 3.85V, capacity: 36mAh.

The back of the battery is built based on patented technologies such as MBT glass-sealed lithium-ion battery technology, ceramic lithium-ion battery technology, laser welding structure technology of shell cover ring seam and glass-sealed explosion-proof valve technology. It has the characteristics of high energy density in the same volume, long service life, fast charging, safety and reliability, and flexible application.

The circuit on one side of the cable.

The circuit on the other side of the cable.

Connect to the BTB connector male socket of the battery cable.

The chip on the in-ear detection FPC is AWINIC AW93105DNR in-ear detection IC, which is a 5-channel low power consumption, high-precision capacitive in-ear detection and touch controller. Each channel can be independently configured as a capacitance detection channel and a reference channel, which can be used for in-ear detection, touch button detection and sliding functions in TWS earbuds. The package size is small and can be placed on the FPC of the in-ear detection, thus saving the space of the motherboard.

AW93105DNR adopts advanced self-capacitance technology, and with the help of AWINIC’s in-ear detection algorithm and sliding algorithm, it can accurately identify operations such as wearing and removing TWS earbuds, clicking, double-clicking, and sliding. It is used for wearing detection function in this product.

Screen printing 2Y BF integrated lithium battery protection IC.

The BTB connector male socket used to connect the motherboard.

All components of Nothing Ear (Stick) true wireless earphones.

03/ Summary

Nothing ear (stick) is a new addition to the product line. In appearance, it inherits the design style of a generation of family, but it also brings new surprises. The unique charging case design similar to lipstick is small, light and portable, and the rotary cockpit switch is cool. Earbuds is a handle-shaped semi-in-ear transparent design, which complements a large number of details to show the beauty of industrial design.

In terms of internal structure configuration, based on the unique shape design, the internal space of the cavity is perfectly utilized, and the product volume is well controlled. The charging case is equipped with a Type-C power input board and function buttons inside the top knob, and is connected to the main board inside the cockpit through wires. The cockpit is equipped with a 350mAh long lithium battery, and the TPS SY8809 chip is used on the motherboard to manage charge and discharge. TPS SY5320 overvoltage and overcurrent protection IC, Chipsea CS32F035 microcontroller, etc. are also used.

In terms of main configuration inside the earphone, BES BES2500YA ultra-low power bluetooth audio SoC is adopted, which supports dual-mode Bluetooth 5.2, open adaptive noise reduction and AI voice. Equipped with AWINIC AW86862 pressure sensing IC, it cooperates with the pressure sensor to realize various function control. The two in-ear detection sensors cooperate with the AWINIC AW93105DNR chip to realize the automatic pause when the earphone is removed, and the playback function can be resumed when the earphone is worn. The discrete design of the in-ear detection and pressure-sensitive button chips allows the capacitive detection chip to be placed next to the in-ear detection sensor. The pressure-sensitive detection chip can be placed next to the pressure-sensitive sensor, and even the in-ear detection chip AW93105DNR is placed on the in-ear detection FPC. In this way, on the one hand, the analog signal of the sensor can be converted into a digital signal through the chip as soon as possible to avoid signal interference, and on the other hand, the area occupied by the motherboard is saved.

The built-in battery of the earphone uses MBT CTSS lithium-ion battery with a capacity of 36mAh and a voltage of 3.85V. The TPS SY5501 power management PMIC is responsible for the charging and discharging protection of the built-in battery. In terms of acoustic devices, the size of the dynamic driver is 12.6mm, and three XINGANG MEMS microphones are used to pick up sound together, with a noise reduction algorithm to achieve a clear voice call effect.

Source: 52audio

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  1. Please add an explanation on how to remove the spinning top part. That’s the most important thing to get inside and you didn’t mention it. Thanks!

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