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| AirPods Pro MWP22H internal circuit diagram with XHH-ZJ5DJ board, SY3408 power IC, 2R2 coil, sensor, battery and key components. |
Apple AirPods Pro MWP22H Circuit Overview.
The Apple AirPods Pro MWP22H is part of the first-generation AirPods Pro family, and its compact electronics are built around a highly integrated PCB, miniature battery, sensors, microphones, wireless communication circuits, and audio components. For technicians and electronics enthusiasts, the internal board is especially interesting because several important components are packed into a very small space.
This guide focuses on the circuit information provided for the XHH-ZJ5DJ board, including the reported SY3408 power IC, 2R2 boost coil, A25MB and 1AM transistors, 0155 sensor marking, BPIT573-8302 IC marking, internal battery, microphone, speaker, and 24.000 MHz crystal.
It is important to distinguish board markings from officially published Apple schematics. Some component roles discussed below are engineering interpretations based on the visible circuit arrangement and component markings rather than an official Apple schematic.
AirPods Pro MWP22H Main Specifications.
The main identification details supplied for this circuit are:
Model / Product: Apple AirPods Pro MWP22H
Main Board Marking: XHH-ZJ5DJ
Main Battery Rating: 3.7V, 1000mAh
Power / Control IC Marking: SY3408-2317A5-60M198
Sensor Marking: 0155
Boost Coil: 2R2
Transistor Markings: A25MB and 1AM
Additional IC Marking: BPIT573-8302
Crystal Oscillator: 24.000 MHz
Earbud Battery Rating: Approximately 3.7V, 40mAh, according to the supplied board information
Speaker Impedance: Approximately 19Ω, according to the supplied information
The MWP22H name is also used in product listings for the first-generation AirPods Pro package, so it should not automatically be treated as the exact PCB identification number for every internal board.
AirPods Pro Internal Circuit Architecture.
The circuit can be understood as several functional blocks rather than as one single circuit.
The battery provides the primary DC supply. Power-management components regulate and route this energy to different sections. The wireless and audio electronics handle Bluetooth communication and sound processing, while sensors and microphones provide user-detection and environmental input.
A simplified signal flow looks like this:
Battery → Power Management → Regulated Power Rails → Wireless / Audio / Sensor Circuits
At the same time:
Bluetooth Audio Data → Audio Processing → Speaker
And for user interaction:
Sensor / Microphone Input → Control & Processing → Device Response
This type of functional separation is useful when troubleshooting because a complete failure does not always mean that the main IC itself is damaged.
Battery and Power Supply Circuit.
The supplied circuit information identifies the main battery as a 3.7V lithium-ion cell with a stated capacity of 1000mAh.
This battery is the primary energy source for the associated power-management circuit. In a compact wireless device, the battery voltage is not necessarily sent directly to every component. Different sections can require different voltage levels, so regulation and conversion are necessary.
The battery path should therefore be considered one of the first areas to inspect when the device shows symptoms such as:
No power
Very short operating time
Charging failure
Random shutdown
Failure to respond
Excessive current consumption
A battery reading that looks normal with no load does not automatically prove that the battery is healthy. Voltage drop under load, charging behavior, connector condition, and abnormal current consumption can also reveal a fault.
SY3408 Power IC and Control Circuit.
The board information identifies the SY3408-2317A5-60M198 as an 8-pin power-control IC.
From a circuit-analysis perspective, this section is important because the surrounding components suggest a switching power stage. The IC is associated with the 2R2 inductor and transistor components, forming part of the power-conversion network.
The exact internal function of a marked IC should not be assumed without a verified datasheet or manufacturer schematic. However, a power-management IC in this type of circuit can typically be involved in voltage regulation, switching control, charging management, or protection functions.
The practical repair approach is to check the input supply, output rails, nearby capacitors, inductor continuity, and switching components before replacing the IC.
2R2 Boost Coil and Power Conversion.
The 2R2 component is identified as an inductor.
In compact DC-DC converter circuits, an inductor stores energy in a magnetic field and releases it as part of the switching process. Depending on the topology, the surrounding circuit can step voltage up, step it down, or regulate it efficiently.
Therefore, the 2R2 coil should not be considered just a passive filter without examining its surrounding components.
A damaged or open inductor can interrupt the power path and may produce symptoms such as:
Missing supply voltage
Failure of a downstream circuit
No startup
Abnormal current draw
Intermittent operation
When measuring the coil, technicians should check continuity and compare the resistance with a known-good board where possible.
A25MB and 1AM Transistors.
Two transistor markings are reported on the board:
A25MB
1AM
These devices appear to belong to the power-control section. In miniature switching circuits, transistors can act as electronic switches and can be used to control current paths, gate other devices, or participate in voltage-conversion stages.
The exact semiconductor type and pin configuration should be verified from the package marking and a reliable component reference before performing replacement.
For repair work, blindly installing a transistor based only on a similar-looking package can create a new fault. Pin configuration, polarity, voltage rating, current rating, and switching characteristics all matter.
0155 Sensor Circuit.
The board information identifies 0155 as a sensor-related marking.
Sensors are essential to the AirPods Pro user experience because the earbuds need to detect physical interaction and operating conditions. In a true wireless earbud, sensor systems can be used for functions such as in-ear detection, motion detection, and other user-interaction features.
The 0155 marking should not automatically be described as a specific sensor type without a verified component reference. It is safer to treat it as a board-level sensor identification unless the exact package and circuit documentation are available.
If the sensor section is suspected, inspect the sensor area for contamination, cracked solder joints, damaged flex connections, and abnormal supply voltage before concluding that the IC itself has failed.
BPIT573-8302 IC and Audio Section.
Another important marking in the supplied board information is BPIT573-8302.
The original source describes this device as a power and audio-processing IC. Because Apple uses highly integrated and custom electronics, the exact internal function of a proprietary chip cannot be confirmed simply from the top marking.
From a repair perspective, this chip should be considered part of the main processing architecture rather than assuming that every audio problem originates from it.
A no-sound problem, for example, can also be caused by:
Speaker damage
Broken flex or board connection
Contamination
Power-rail failure
Bluetooth or software pairing problems
Audio signal-path faults
Damaged passive components
Replacing a major IC should therefore be the last step after basic electrical tests.
Microphone and Noise-Related Circuit.
AirPods Pro use extremely small MEMS-style microphone technology and multiple acoustic paths to support calls and noise-control features. Teardown documentation also shows how densely integrated the microphones and other modules are inside the earbuds.
A microphone fault can affect phone calls, voice input, and noise-control performance.
Before assuming a microphone IC or module has failed, check the microphone opening, acoustic mesh, solder joints, flex connections, and related power or signal lines.
Cleaning is often more appropriate than immediate component replacement when the problem is caused by dust, debris, or blocked acoustic openings.
Earbud Internal Battery.
The supplied circuit information lists an internal earbud battery of approximately 3.7V and 40mAh.
A very small battery is necessary to maintain the low weight and compact size of the individual earbud. The battery must support wireless communication, audio processing, sensing, and other functions without adding significant physical bulk.
Battery-related problems can appear as:
One side draining much faster than the other
Earbud not turning on
Rapid shutdown
Failure to charge
Battery percentage behaving abnormally
Because lithium-ion cells are sensitive to improper charging and physical damage, battery replacement should be handled carefully using appropriate tools and safety procedures.
19Ω Speaker and Audio Output.
The board information identifies a speaker impedance of approximately 19Ω.
Speaker impedance describes the electrical load presented to the audio output stage. The actual impedance of a miniature speaker can vary with frequency, so the printed or nominal value should not be treated as a simple fixed resistance measurement.
If an earbud has very low volume, distorted audio, or no audio at all, testing should include the speaker, connection points, audio path, and power rails.
A speaker that measures differently from a known-good unit can provide useful evidence of a hardware fault.
24.000 MHz Crystal Oscillator.
The supplied board data identifies a 24.000 MHz crystal oscillator.
A crystal oscillator provides a stable reference clock used by electronic circuits that require accurate timing. In wireless and digital systems, clock stability is important for synchronization and communication.
One important correction is necessary here: 24.000 MHz is not the Bluetooth operating range of the AirPods. It is a reference-clock frequency associated with timing circuitry.
So, the 24 MHz component should be analysed as part of the clock-generation system rather than as a wireless-distance specification.
Front and Back Side Circuit Inspection.
A useful AirPods Pro PCB inspection should always include both sides of the board.
The front side normally reveals the major ICs, power components, connectors, sensors, and passive networks that are most useful for initial identification.
The back side can reveal additional routing, passive components, test points, shielding structures, and connections that are not visible from the main component side.
When comparing circuit images, technicians should look for:
Board marking
IC top markings
Coil value
Transistor locations
Sensor position
Battery connection
Flex connectors
Ground points
Power-rail components
Visible corrosion or physical damage
This is much more useful than trying to identify a faulty component from a single photograph.
AirPods Pro Circuit Troubleshooting Steps.
When an AirPods Pro unit does not work, a systematic diagnosis is safer than immediately replacing expensive ICs.
Step 1: Check the Battery.
Measure battery voltage using appropriate test equipment and confirm whether the voltage remains stable during operation or charging.
A battery that collapses under load may need replacement even when its open-circuit voltage appears reasonable.
Step 2: Inspect the Power Path.
Check the battery connection, protection components, coil, transistors, capacitors, and the SY3408 area.
Look for short circuits on the main power rail before applying unnecessary power.
Step 3: Check the Switching Section.
Inspect the 2R2 inductor and the nearby A25MB and 1AM transistor components.
An open coil, shorted capacitor, or damaged switching transistor can prevent the expected voltage rail from appearing.
Step 4: Check Sensors and Flex Connections.
If charging and power appear normal but specific functions fail, inspect the sensor area and flex connections.
Small mechanical damage can disconnect an otherwise healthy circuit.
Step 5: Check the Audio Path.
For a no-sound complaint, test the speaker and inspect its electrical connection before suspecting the main audio-processing IC.
Step 6: Check Bluetooth and Software Behavior.
Not every AirPods problem is caused by hardware.
Resetting the AirPods, removing and re-pairing them, checking device settings, and testing with another compatible device can help separate software or pairing problems from PCB faults.
Common AirPods Pro Problems and Possible Causes.
AirPods Pro Not Turning On.
Possible causes include a deeply discharged or failed battery, charging-path problems, damaged power components, or a fault on the main power rail.
AirPods Pro Not Charging.
Check the charging contacts, battery connection, power-management section, and the charging case before replacing an internal IC.
One AirPod Not Working.
A single-earbud failure may be related to its battery, speaker, sensor, connection, charging contact, or internal board rather than the entire system.
AirPods Pro Sound Distortion.
Distorted sound can be caused by the speaker, acoustic blockage, internal damage, moisture contamination, or electronic faults.
Apple has also documented a service program for certain first-generation AirPods Pro units manufactured before October 2020 that may develop crackling/static sounds or problems with Active Noise Cancellation. Apple states that eligible confirmed units were serviced or replaced through its program, subject to its service conditions.
How to Use the Circuit Diagram for Repair.
A circuit image becomes much more useful when each component is linked to a function.
For example, the 3.7V battery represents the primary energy source. The SY3408 belongs to the power-management area, while the 2R2 coil and transistor stage are associated with switching and voltage conversion.
The BPIT573-8302 marking belongs to another important IC section, while the 0155 marking is associated with the sensor area. The 19Ω speaker is part of the audio output path, and the 24.000 MHz crystal provides a stable timing reference.
This functional approach makes troubleshooting much easier than simply memorizing component numbers.
Important Repair Precautions.
AirPods Pro electronics are extremely compact, and many internal components are difficult to replace without microscope-level inspection and suitable rework equipment.
Before attempting board repair:
Disconnect power where possible.
Avoid accidental short circuits around the battery.
Do not probe unknown test points with excessive pressure.
Verify component pinout before replacement.
Use ESD protection when working on sensitive electronics.
Avoid overheating the battery or nearby flexible circuits.
Confirm the fault with measurements before replacing an IC.
Opening the earbud or charging case can also cause mechanical damage because the internal assemblies are tightly fitted and can be difficult to separate without specialised tools. Professional teardown documentation shows the complexity of the internal construction.
Official Apple Support and Service Information.
For model identification, serial-number information, cleaning guidance, service options, and other official instructions, use Apple's AirPods Support resources.
Apple's official AirPods Pro sound-issues service page is also useful when checking whether a first-generation unit may have been affected by the documented sound problem program.
Note: Component markings and circuit functions in this guide are based on the supplied board information and visible circuit analysis; always verify the exact component and pinout before repair or replacement.
Disclaimer: This article is provided for educational and electronics-analysis purposes. AirPods Pro contain delicate lithium-ion batteries and miniature surface-mount electronics. Incorrect probing, soldering, battery handling, or component replacement can permanently damage the device or create a safety hazard. Do not treat this article as an official Apple service manual or factory schematic. For warranty, service-program eligibility, or official repair information, use Apple Support or an Apple Authorized Service Provider.
