Sennheiser MOMENTUM True Wireless 4 is equipped with TrueResponse transducer system and 7mm dynamic driver. With Qualcomm aptX Lossless audio technology, it provides CD-level sound quality experience. In cooperation with IDMT, a new sound personalization function is developed to intelligently customize personalized audio profiles. It supports 5-band equalizer adjustment, which can adapt to audio content to ensure the same high-quality experience at different volume levels.
MOMENTUM True Wireless 4 supports adaptive noise reduction function, matching more comfortable noise reduction effect for different usage scenarios. Supports adjustable transparency mode, and can preset the ambient sound intensity according to the usage scenario. Adopts 3-MIC system to provide high-quality voice pickup and ensure clear calls. The earbuds has a single battery life of up to 7.5 hours, and can provide 30 hours of noise reduction listening with charging case. Plus, it supports Qi wireless charging. Let’s take a look at the detailed teardown report of Sennheiser MOMENTUM True Wireless 4.
01/ Sennheiser MOMENTUM True Wireless 4 Charging Case Teardown
Disassemble the charging case shell and take out the charging bin structure and battery.
The bottom structure of the charging bin, with the motherboard fixed by screws.
The wireless charging receiving coil is set on the magnetic shielding sticker.
The charging case has a built-in cylindrical rechargeable lithium-ion battery, model: 14500-850, rated capacity: 820mAh, nominal voltage: 3.6V, rated watt-hour: 2.952Wh, charging limit voltage: 4.2V, from Huizhou Highpower Technology.
Remove the screws and remove the motherboard.
The bottom structure of the charging bin is equipped with five magnets to adsorb and fix the earbuds and the charging case lid.
The circuit on one side of the charging case motherboard.
The circuit on the other side of the charging case motherboard.
LED indicator.
IC with silkscreen U2 N.
LPS LP5305 overvoltage and overcurrent protection IC is used to protect low voltage systems from abnormally high input voltage. When working, the IC continuously checks the input voltage, input current and battery voltage. When the protection state occurs, the power MOS will be turned off at the same time.
LP5305 is a safety device to ensure the prevention of accidents. If the input voltage exceeds the OVP threshold voltage level, the power MOS will be turned off within 1μs. The current limit can be adjusted by an external resistor between ISET and GND. And the current is also limited to prevent the battery from charging with excessive current. LP5305 also monitors the lithium-ion battery voltage, and when the battery voltage exceeds 4.35V, the IC will turn off the MOS. Other features include overtemperature protection and undervoltage lockout (UVLO). LP5305 adopts a space-saving DFN-8 package.
IC with silkscreen Z69.
MCU with silkscreen KF6288M6 for charging case control.
NuVolta NU1680 is a small-size, highly integrated wireless power receiver. It integrates a synchronous rectifier, does not require an external bootstrap capacitor, and has the characteristics of high efficiency and low cost. It can provide a wide range of 3.5V to 9V regulation, suitable for different applications. And the output voltage can be adjusted to track the battery voltage to reduce the power consumption of the charging system.
NuVolta NU1680 can communicate with the transmitting system through ASK, and the communication complies with WPC V1.2.4. FOD parameters can be configured through the I2C interface or external resistors. Support I2C interface for communication. Provide external interrupts, battery voltage ADC value, output current, etc. NU1680 also supports standard protection functions such as overcurrent protection, short circuit protection, overvoltage protection and thermal shutdown.
Silkscreen C106 capacitor.
Silkscreen 8891Z IC.
SGMICRO SGM41523D lithium battery charger, charging voltage and current can be set using resistors, and the charging current can be set in the range of 0.2A to 2.5A. It has other safety features such as overvoltage/overcurrent protection, foldback hold, input undervoltage lockout, battery temperature monitoring, and thermal shutdown.
Lithium battery charger peripheral power inductor.
IC with silkscreen OH RQ.
IC with silkscreen 21A KO.
IC with silkscreen OA RD.
02/ Sennheiser MOMENTUM True Wireless 4 Earbuds Teardown
Disassemble the sound cavity, and fix the battery and motherboard in the back cavity with a bracket.
The front cavity is equipped with a PCB board, which connects the speaker and microphone, etc.
Take out the small board and FPC in the front cavity.
The back of the earbud speaker module.
After actual measurement, the speaker module has a diameter of about 8mm.
Separate the FPC and take out all the components in the back cavity.
The LDS bluetooth antenna and touch detection electrode are printed on the bottom of the back cavity.
The small board in the front cavity and the circuit on one side of the FPC.
The circuit on the other side.
The MEMS microphone of the laser engraved 342o BUM is a feed-back noise reduction microphone that picks up sound with the noise reduction function.
The IC with silk screen X2G.
The metal copper column connected to the charging case.
Infrared distance sensor, used for in-ear detection function, to automatically pause music playback when the earbud is removed, and automatically resume playback after wearing.
IC with silkscreen IM Ex.
LED indicator, used to feedback connection status and remaining power information.
BTB connector for connecting the small board to the main board.
Separate the internal bracket of the back cavity from the fixed battery and main board.
The circuit on one side of the earbud main board. The soft and hard board combination process is adopted, and the three PCB boards are connected by soft FPC to better utilize the internal space of the earbuds.
The circuit on the other side of the earbud main board.
ADI ADAU1788 audio DSP chip, dual-channel ADC, independent DAC, used for the ANC function of earbuds.
24.576MHz crystal oscillator, providing clock for the audio DSP chip.
IC with silkscreen C 2EU.
IC with silkscreen 2AC NZ.
The MEMS feedforward noise reduction microphone of the laser engraving 343o BUM is used to pick up external environmental noise.
Qualcomm QCC5181 bluetooth audio SoC is part of the second-generation Qualcomm S5 audio platform. Supports Bluetooth 5.4, fully meeting the requirements of supporting the new Bluetooth LE Audio (low-power audio) use case, including Auracast broadcast audio. It can also support Snapdragon Sound technology.
Qualcomm QCC5181 supports aptX audio codec technology, including aptX Adaptive and aptX Lossless, up to 24bit/96KHz. Supports aptX Voice technology, the eighth-generation Qualcomm cVc echo cancellation technology and noise suppression technology. Integrates Qualcomm adaptive ANC technology, including feedforward, feedback, hybrid and adaptive, and supports third-party innovation through Qualcomm extensions.
32.000MHz crystal oscillator that provides clock for bluetooth chip.
Bluetooth chip external memory, used to store configuration files, firmware and other related data.
The third MEMS silicon microphone of the laser engraving 343o BUM is a call microphone, which is used to pick up human voice for voice call function.
The main board connects to the BTB connector of the small board inside the front cavity.
The peripheral circuit on the back of the noise reduction chip.
The metal dome that connects the bluetooth antenna and the touch detection electrode.
Vinka VKD233HS touch detection IC, with 1 touch button, can be used to detect the touch action of the human hand on the external touch button. The chip has a high degree of integration and only requires very few external components to detect the touch button. It provides 1 output function, and the output level and output mode can be selected through the IO pin. The chip integrates a voltage regulator circuit to provide a stable voltage for touch detection, which can reduce the occurrence of key detection errors and improve reliability.
IC with silkscreen IM GA.
Lithium battery protection IC with silkscreen GF at the solder joint between the battery and the motherboard.
The steel shell button battery equipped with the earbuds, model: MC1254S, nominal voltage: 3.80V, rated capacity: 72mAh 0.274Wh, from MBT.
The other side of the steel shell button battery. It adopts the MBT patented micro-battery abnormal heating blocking mechanism, based on the structural integration of the all-metal thermal conductive structure (metal cover and shell) and the temperature sensing switch (PPTC).
When the battery is abused and abnormally heated, the all-metal heat-conducting structure can quickly collect the heat inside the battery and conduct it to the temperature sensing switch. The internal resistance of the temperature sensing switch increases exponentially before the battery diaphragm fails, blocking the abnormal battery use circuit and preventing the battery from being abused or damaged. When the abnormal heating of the battery slows down or disappears, the internal resistance of the temperature sensing switch can return to the normal use level. If the battery is not damaged, the protective mechanism can continue to be used effectively.
All components of Sennheiser MOMENTUM True Wireless 4 TWS earbuds.
03/ Summary
Sennheiser MOMENTUM True Wireless 4 continues the brand’s characteristic family design and is highly recognizable. The rounded square charging case is compact and portable, and is covered with fabric, which brings a soft and comfortable texture. The earbuds adopt a bean-shaped in-ear design, and the body is processed by metal-like technology, showing an excellent texture. The ergonomic design, with multiple pairs of silicone earplugs and earwings, provides a comfortable and stable wearing experience.
The charging case is equipped with an 820mAh cylindrical rechargeable lithium-ion battery. The wired charging uses the SGMICRO SGM41523D lithium battery charger, and the wireless charging is handled by the NuVolta NU1680 wireless power receiver. It uses the LPS LP5305 overvoltage and overcurrent protection IC, as well as an MCU for overall control.
The internal structure of the earbuds is highly integrated, and the utilization of the internal space is improved through the combination of soft and hard boards. The earbuds has a built-in 7mm dynamic driver and three MEMS microphones for sound pickup. The built-in steel shell button battery has a capacity of 72mAh and comes from MBT. The motherboard uses Qualcomm QCC5181 bluetooth audio SoC, ADI ADAU1788 audio DSP chip, and Vinka VKD233HS touch detection IC, etc.
PS: Translated from 52audio
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