Nothing CMF Buds are equipped with a 12.4mm dynamic driver and supports Ultra Bass 2.0 dynamic bass enhancement technology. Tuned by Nothing, it has an audio experience that adapts to various music styles. It supports ANC and transparent mode, with a maximum noise reduction depth of 42dB. It supports intelligent wind noise reduction, and through the through-type structural design, it is equipped with an intelligent wind noise reduction algorithm to greatly enhance call clarity. The single battery life is up to 6.5 hours, and a total of 35.5 hours of music playback.

We have previously teardown the Nothing products including: Nothing CMF Buds Pro, Nothing Ear (2) and Nothing Ear (Stick). Let’s take a look at the detailed teardown report of Nothing CMF Buds.

01/ Nothing CMF Buds Charging Case Teardown

Disassemble the charging case shell and take out the charging bin structure. The motherboard is fixed by screws inside the cavity, and the battery is fixed by positioning grooves and double-sided tape. The FPC is fixed by a cover at the bottom of the charging bin.

Remove the screws and take out the motherboard and battery.

The circuit on one side of the charging case motherboard.

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

ZIF connector connected to the FPC.

Two LED indicators of different colors are used to feedback bluetooth pairing and charging status.

Injoinic IP5528 TWS charging bin management SoC is a multi-function power management SOC that integrates MCU, boost converter, lithium battery charging management, and battery power indication, providing a complete solution for TWS charging bin. Thanks to the high integration and rich functions of IP5528, only a few peripheral devices are required in application, which effectively reduces the size of the overall solution and reduces BOM cost.

IP5528 supports the follow-up charging function, which can achieve 10mV fine step adjustment of the charging voltage in the range of 3.2~5.5V, which can effectively improve the conversion efficiency of the charging case battery to the earbud battery by 15%~20%, thereby increasing the overall battery life by 15%~20%.

In application, IP5528 only needs one inductor to realize the buck-boost function, and supports low-cost inductors and capacitors. The synchronous boost system of IP5528 provides a rated output current of 400mA, and the conversion efficiency is as high as 93%. When lightly loaded, it automatically enters the sleep state, and the quiescent current is reduced to 15µA.

IP5528 adopts switch charging technology, provides a rated charging current of 1A, and the charging efficiency is as high as 90%. Built-in chip temperature protection and input voltage intelligent adjustment charging current. IP5528 has a built-in 12bit ADC, which can accurately measure battery voltage and current. Supports 1/2/3/4 LED power display and digital display. According to the product manual, IP5528 also supports output voltage of 3.2V~5.2V and supports fast charging for headphones.

Charging bin manages SoC peripheral inductors.

Multi-function button.

TVS tube with silk screen T18 is used for input overvoltage protection.

Overvoltage and overcurrent protection IC with silk screen CRYKC is used to protect the downstream low-voltage system from abnormally high input voltage.

iCM CM1125-BBC integrated MOSFET single-cell lithium battery protection IC. By detecting the voltage and current of the battery, it can protect the battery from overcharge, overdischarge and overcurrent.

The charging case has a built-in lithium-ion battery, model: JHY751534, nominal voltage: 3.8V, rated capacity: 460mAh 1.748Wh, production date: February 1, 2024.

Remove the cover, and the bottom of the charging bin is the FPC structure for charging earbuds.

Remove the FPC. FPC circuit for charging earbuds.

Pogo Pin connector for connecting earbuds to charge them.

Hall element with silkscreen qH 3v, used to sense the change of magnetic field when the charging case is opened/closed, and then notify the charging case MCU and earbuds to pair or disconnect with the connected device.

02/ Nothing CMF Buds ANC Earbuds Teardown

Disassemble the back cover of the earbud stem.

The inner structure of the cover is equipped with a bluetooth antenna and a touch detection patch.

The motherboard is fixed inside the cavity and connected to the FPC through a BTB connector.

Remove the motherboard.

The bottom structure of the earbud stem cavity is fixed with a square magnet, which is adsorbed and fixed to the charging case.

The inside of the noise reduction microphone pickup hole is protected by a dust net.

The BTB connector of the FPC connected to the motherboard of the internal component of the cavity is from OCN, model: OK-128GM010/2-35.

The circuit on one side of the earbud motherboard.

The MEMS microphone with silkscreen MF52 D223 is a noise reduction microphone, which is used for the noise reduction function to pick up external environmental noise, from MEMSensing.

The BTB connector connected to the FPC is from OCN, model: OK-128GF010/2-35.

The metal dome connected to the bluetooth antenna and the touch detection patch.

The crystal oscillator used to provide clock.

The circuit on the other side of the earbud motherboard.

BES BES2700IHC bluetooth audio SoC, supports Bluetooth V5.4 and FF+FB Hybrid ANC, for wireless connection and audio data processing.

Metal connector connected to charging case, with transparent rubber ring for waterproofing.

Another MEMS call microphone, laser engraved model: MF25 D118. The two microphones work together to pick up sound, and with the noise reduction algorithm, provide clear calls.

Disassemble the earbud head.

In-ear detection sensors are attached around the back cavity, which are used to automatically pause the playback when the earbud is removed, and automatically resume the playback function after wearing.

Internal structure of the front cavity, the battery is fixed by a bracket.

Remove the FPC inside the back cavity.

Remove the battery and FPC.

Remove the earbud battery.

The earbuds have a built-in steel shell button battery, model: CH1140AA, nominal voltage: 3.85V, capacity: 45mAh.

FPC circuit.

iCM CM1126B-DAC with shipping mode two-in-one single-cell battery protection IC, suitable for protection circuits for single-cell lithium-ion/lithium-polymer rechargeable batteries.

Front cavity internal speaker structure.

The speaker uses biofiber + customized TPU dynamic driver.

After actual measurement, the speaker diameter is about 12.70mm.

All components of Nothing CMF Buds true wireless noise cancellation earphones.

03/ Summary

The Nothing CMF Buds charging case adopts a rectangular design and an aluminum alloy knob, which can be used with a lanyard. The earbuds adopt a long stem in-ear design, combining glossy and matte textures – comfortable and stable to wear.

The charging case is equipped with a 460mAh lithium battery and uses the Injoinic IP5528 TWS charging bin management SoC to manage charging and discharging. It supports the follow-up charging function, which can effectively improve the battery conversion efficiency by 15%~20%, thereby increasing the overall battery life by 15%~20%. It uses the iCM CM1125-BBC lithium battery protection IC to protect the charging and discharging of the built-in battery.

The earbuds are equipped with a 12.4mm composite diaphragm dynamic driver, a built-in 3.85V/45mAh steel shell button battery, and an iCM CM1126B-DAC with shipping mode two-in-one single-cell battery protection IC. The motherboard is equipped with a BES BES2700IHC bluetooth audio SoC and uses two MEMS microphones for sound pickup.

PS: Translated from 52audio

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