Apple AirPods 4 continues the semi-in-ear design of the previous model, with a new internal ear-cavity structure and comfortable contour, providing a comfortable, refreshing, and secure wearing experience. It adopts a new acoustic architecture, Apple-designed low-distortion driver unit, and a customized high dynamic range amplifier to bring deeper bass extension and clear/bright treble. It also supports personalized spatial audio with dynamic head tracking to provide surround sound.
Apple AirPods 4 upgrades the H2 chip, providing more powerful computing support and numerous intelligent functions. Including support for Active Noise Cancellation and transparent mode. Supports adaptive audio, which can automatically adjust transparent mode and ANC. Supports conversation perception, automatically lowers the audio volume when communication is detected, and automatically restores it after the conversation ends. Support voice highlighting function to reduce background noise and provide clear calls. Supports adaptive EQ, which automatically adjusts the music effect.
Plus, it uses pressure-sensitive buttons to provide precise interaction. Supports head control, providing a convenient and rich interactive experience. The ANC version is equipped with a USB-C wireless charging case, which supports Apple Watch chargers and Qi chargers. The charging case has a built-in speaker and supports independent headphone positioning function. The maximum single battery life of the earbuds is 5 hours, and the comprehensive battery life reaches 30 hours.
We have previously disassembled Apple products including: AirPods Pro 2 (USB-C), AirPods Pro 2 (Lightning), AirPods Pro, AirPods 3, AirPods 2, Apple AirPods, Beats Fit Pro, Beats Studio Buds, Beats Powerbeats PRO, Apple AirPods Max, Apple HomePod Mini and Apple HomePod, etc. Let’s take a look at the detailed teardown report of Apple AirPods 4 ANC.
01/ Apple AirPods 4 ANC Charging Case Teardown
Disassemble the charging case shell and take out the charging bin structure.
There are multiple magnets at the bottom of the charging bin to fix the earbuds and the charging case lid.
The metal dome connector for charging the earbuds.
All components are fixed inside the cavity by the bracket.
The mainboard unit structure on one side of the bracket is connected to the wireless charging receiving coil board through the FPC.
Pick up the connector and separate the FPC.
The battery is fixed on the other side of the bracket.
The bottom structure of the bracket is equipped with a Type-C charging interface and a speaker.
Pick up the connector and remove the battery.
The charging case has a built-in lithium-ion battery pack, model: S2103, nominal voltage: 3.852V, rated capacity: 345mAh, rated energy: 1.329Wh, charging limit voltage: 4.45V.
Remove the screws, remove the mainboard and speaker.
The charging case has a built-in speaker for headphone positioning and sound, and is connected to the mainboard through contacts.
After actual measurement, the speaker size is 10.15mm*8.44mm.
The circuit on one side of the charging case motherboard is equipped with a USB-C charging dock.
The circuit on the other side of the charging case motherboard.
The bluetooth antenna of the charging case is used to communicate with the mobile phone.
The IC with silkscreen 46H8.
The IC with silkscreen 9M14F7.
TI BQ25118B charger, and the Maxim MAX98357B Class D audio amplifier, with the silkscreen model “+AKN”, is used to drive the charging case speaker.
IC with screen printing 47320I.
IC with screen printing 46H8.
Nordic nRF52832 multi-protocol general-purpose SoC, supporting Bluetooth 5.0, NFC, ANT and 2.4GHz protocols. At its core is an ARM Cortex M4 CPU running at 64MHz, which can handle demanding applications and communication tasks in a short time, allowing the CPU to continue to handle more tasks or return to sleep mode, thus saving power consumption. The nRF52832 and all SoCs in the nRF52 series are flash-based, which is ideal for device firmware upgrades (DFU).
32.000MHz crystal oscillator for clocking.
BTB connector for connecting battery leads.
ST STM32L496WGY6P microcontroller. The STM32L496xx series is based on the high-performance Arm Cortex-M4 32-bit RISC core, operating at up to 80MHz. The Cortex-M4 core has a single-precision floating-point unit (FPU) that supports all Arm single-precision data processing instructions and data types. It also implements a complete set of DSP instructions and a memory protection unit (MPU) to enhance application security.
ICs with silkscreen X86 LP and 1DH 4WG.
BTB connector connected to the wireless charging board.
ICs with silkscreen 26E3W.
Take out the board with the wireless charging receiving coil.
The wireless charging receiving coil on the cavity wall is covered with a magnetic shielding sticker.
The circuit on one side of the board, the main IC is sealed with black hard glue.
Bourns thermal protection device, used for wireless charging coil temperature detection.
A magnet is set on the other side of the board for magnetic fixation.
FPC connects to the BTB connector of the motherboard.
The other end of the FPC is used to detect the state of the charging case lid (open or closed) and realize the Hall element of the open cover connection.
02/ Apple AirPods 4 ANC Earbuds Teardown
Disassemble the earbud cavity. The battery is fixed by a bracket inside the front cavity, and a protection IC with a QR code is set on the FPC on the back of the battery.
A MEMS microphone is set inside the back cavity, and the FPC extends into the earbud-stem.
Remove the battery and speaker.
The earbud has a built-in steel shell button battery, which is welded to the FPC, and the previous model is connected by a connector.
Remove the transparent bracket and take out the speaker.
The front of the earbud speaker. According to the official introduction, the low-distortion driver unit designed for Apple provides rich audio details.
The bottom structure of the front cavity, an inward-facing microphone is fixed inside the acoustic nozzle filter.
Information on the label of the built-in steel shell button battery in the earphone, model: A3087, rated capacity: 32.1mAh/123mWh, nominal voltage: 3.83V, charging limit voltage: 4.35V, from SDI.
Open the tail plug at the bottom of the earbud-stem.
Take out the FPC inside the front cavity and the components inside the earbud-stem. All the components inside the earbuds are connected to an FPC.
There is a call microphone inside the tail plug.
The circuit of the FPC inside the earbud.
The MEMS microphone of the laser engraving S 341 is an inward-facing microphone, used for Active Noise Cancellation, adaptive equalization, etc.
The optical in-ear detection sensor is used to automatically pause the playback when the earbud is removed and automatically resume the playback after wearing.
The MEMS microphone of the laser engraving G205 is a noise reduction microphone, used to pick up environmental noise.
The back FPC of the SIP package H2 chip is equipped with an IC with a silk-screen QR code, which is presumed to be a detection chip for the force sensor. The force sensor is connected below for pressure control.
The bracket of the LDS laser antenna is fixed on the H2 chip.
Remove the bluetooth antenna bracket.
H2 chip of the SiP package system.
The MEMS microphone of the laser engraving S 341 is a call microphone, used to pick up human voices during voice calls.
All components of Apple AirPods 4 ANC earphones.
03/ Summary
Apple AirPods 4 continues the family-style smooth and rounded design style, feels comfortable, but is prone to scratches, fingerprints and oil stains. The charging case is more compact and portable, and still incorporates the independent finding function of AirPods Pro 2. The ergonomics of the stem-shaped semi-in-ear earbuds are further optimized to provide a better wearing fit to achieve a better noise reduction effect.
The charging case is equipped with a 345mAh lithium battery, and the wired charging uses a TI BQ25118B charger. Wireless charging is handled by a BROADCOM 59356A2KUBG wireless charging management IC. It is equipped with a speaker unit, driven by a Maxim MAX98357B Class D audio amplifier, and a Nordic nRF52832 multi-protocol general-purpose SoC for wireless communication with the mobile phone. It is also equipped with an ST STM32L496WGY6P microcontroller for charging case control.
The earbud is equipped with a low-distortion driver designed by Apple and three built-in MEMS microphones for accurate sound pickup for functions such as Active Noise Cancellation, Transparency Mode, Dialogue Perception, and Adaptive EQ. They have a built-in steel shell button battery with a capacity of 32.1mAh. The H2 chip in SiP packaging provides powerful computing power support for various functions. Plus, it is also equipped with an optical in-ear detection sensor, a force sensor, and more.
PS: Translated from 52audio
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