Redmi recently held a new product launch conference and released a new K40 series of mobile phones, laptops, TVs and other products, and Redmi’s new true wireless earphones Redmi AirDots 3 also made a surprise appearance. The Redmi Airdots 3 true wireless earphones continues the classic appearance of the previous generation. The earphones is a bean-type in-ear design with a small size, the charging case is a clamshell design, and the plastic body has a matte feel.
Although the appearance is similar, this time Redmi AirDots 3 has been greatly upgraded in terms of internal structure and materials. First, the earphones is equipped with two high-resolution sound units of high-frequency moving iron + low-frequency moving coil. Advantages, both bass sound field and treble details. Secondly, the earphones is equipped with Qualcomm’s next-generation Bluetooth audio SoC QCC3040, supports Qualcomm’s second-generation aptX Adaptive codec, and has passed the Bluetooth 5.2 certification, which has better performance in terms of connection stability and power consumption.
The third point is a major upgrade in interactive functions. Redmi Airdots 3 changes the previous button control of the earphones to touch touch, which makes the body more integrated, and also adds an infrared optical sensor for in-ear detection. The comprehensive configuration has few rivals among products at the same price. Let’s take a look at the detailed disassembly of 52audio.
52audio has teardown the Redmi products, including: Redmi AirDots 2, Redmi AirDots S and Redmi AirDots true wireless Bluetooth earphones.
| 1. Redmi Airdots 3 charging case teardown
After unpacking the box, we have got a preliminary impression of the appearance design of the Redmi Airdots 3 true wireless Bluetooth earphones. The appearance of the previous generation is continued, but the charging interface and the quick pairing button have been upgraded. Next, we will enter the dismantling link to take a look at its structural design and chip material information.
Pry open the charging cockpit to see the internal structure, and there are multiple physical buckle connections on the side.
Light guide at the position of the indicator light.
The internal structure of the charging case, the battery is at the bottom of the charging case, and there is a buffer foam between the main board and the battery.
Inside structure of charging cockpit. There are 5 bar magnets on the inside of the charging cockpit, of which there are two on the left and right earphone sound chambers, and the upper one is for adsorbing the charging case cover.
The charging case uses a soft pack battery, model 101440, energy 2.22Wh, typical capacity 610mAh, minimum 600mAh, rated voltage 3.7V, and limited voltage 4.2V.
The battery protection board has an integrated lithium battery protection IC, which is responsible for the overcharge, overdischarge and overcurrent protection of the battery; there is also a thermistor to detect the battery temperature.
Circuit on the motherboard side.
Circuit on the other side of the motherboard.
Self-recovery fuse at the power input.
The TVS with silk-screen T12 is used for input overvoltage protection.
Silkscreen 0XWA IC.
LPS LP6260, an ultra-low static synchronous boost converter, with a switching frequency of 1.2MHz, supports a variety of protection functions, and has only three peripheral components, which is very streamlined. It is used to boost the battery output of the charging case to charge the earphones.
According to 52audio, audio products from brands such as Xiaomi, OPPO, Huawei, Lenovo, Motorola, Realme, Edifier, QCY, JLab, Skullcandy, Boltune and other brands have adopted a large number of LPS power management solutions.
CHIPSEA CSU32P20, CSU32P20 is an 8-bit CMOS single-chip RISC MCU with 12-bit ADC, built-in 2K×16-bit OTP program memory, 104 bytes of SRAM. It is used to realize charging case control functions such as charge and discharge module management, battery power management, earphones communication, online upgrades and production testing.
Self-recovery fuse at the battery power input.
Gold-plated Pogo Pin for charging earphones.
For the Hall element of silk-screen ANG AW0m, the magnetic field changes when the charging case cover is opened and closed will be sensed by the Hall element, and the charging case will be notified that the MCU and earphones are paired or disconnected with the connected device.
An LED indicator.
| 2. Redmi Airdots 3 earbuds teardown
Let’s continue to disassemble the earphone part of Redmi Airdots 3. The earphone adopts a bean-type in-ear design, the shell is treated with a bright surface, and the touch control is adopted, which looks more integrated.
The earphone shell supports touch control, and the top is an indicator light opening.
The call microphone pickup hole at the bottom of the earphones.
The charging contacts on the inside of the earphones, below are the newly added infrared optical distance sensors, which are used for in-ear detection.
Pressure relief hole and tuning hole near the mouthpiece.
Another pressure relief hole.
The sound mouth has a hole to fit the shape of the moving iron unit, and a fine dust-proof net prevents foreign matter from entering.
Disassemble the earphone along the parting line to see the internal structure.
On the inside and outside of the cover is an FPC-type Bluetooth antenna, and the middle is a touch-sensitive foil.
The internal layout of the left and right earphones is similar.
There is a handwritten L/R logo on the main board, continue to disassemble the front cavity below.
Pry open the motherboard and find that the FPC on the inside is soldered to the motherboard.
The charging board connected to the FPC is fixed with a large amount of white glue.
After taking out the internal structure of the charging plate, the left and right sides are magnets for adsorbing the charging case.
The shell only leaves an opening for the wire of the speaker unit, which is inserted from the mouthpiece during assembly, and the seam of the wire is sealed with glue.
The earphones uses a soft pack battery, model 541112VK, with an energy of 0.16Wh, a rated capacity of 43mAh, and a rated voltage of 3.8V.
The information on the battery cell is consistent with the label.
The wires connect the positive and negative poles of the battery.
The main circuit inside the earphone, the two PCBs are connected through FPC.
The other side of the circuit.
Redmi Airdots 3 true wireless bluetooth earphones uses Qualcomm’s new generation Bluetooth audio SoC QCC3040.
Qualcomm QCC304x series Bluetooth audio SoC, supports bluetooth V5.2, supports Qualcomm aptX™ Adaptive audio coding, combines stability, good sound quality, scalability, low latency and low bit rate audio transmission and other enhanced features; this series of chips It also supports the new Qualcomm TrueWireless™ Mirroring technology, and the left and right earbuds can be quickly switched in multiple usage scenarios. In addition, Qualcomm QCC304x series Bluetooth audio SoC also integrates hybrid active noise reduction technology, supports cVc call noise reduction technology, and can wake up the phone’s voice assistant through touch or button.
According to 52audio, well-known brands such as Anker, Bose, Beyerdynamic, B&O, Cleer, Edifier, Xiaomi, Microsoft, OPPO, vivo, Sony, and 1MORE have adopted Qualcomm’s Bluetooth audio SoC in large numbers.
The regulator IC of silk screen MLY.
Battery protection IC with silk screen 0fA4.
The touch IC of the silk screen HH01F.
Connect the bluetooth antenna and the gold-plated Pogo Pin of the touch sensing FPC respectively.
The black foam outside the indicator light prevents light leakage.
An LED indicator.
The protective cover for the microphone pickup hole.
Laser carving MC45 DL36 MEMS silicon microphone is used for call pickup.
There is a dustproof and waterproof rubber ring at the charging contact position, and there is a filter protection cover outside the infrared optical sensor.
Disassemble the speaker unit from the position of the mouthpiece housing.
The first thing you see is the magnet side of the moving coil speaker, and there are capacitors responsible for frequency division on the small board.
One side of the dynamic speaker diaphragm.
The armature driver is connected to the dynamic driver through a wire.
There is a dust screen inside the tuning hole.
There is a protective cover outside the moving iron unit.
The balanced armature armature driver comes from BELLSING, model BTC305C90012. The armature driver is mainly responsible for medium and high frequency.
One side of the diaphragm of the dynamic driver. Dynamic driver can bring better bass effect.
The diameter of the dynamic driver is about 6.05mm.
All components of Redmi Airdots 3 true wireless bluetooth earphones.
The Redmi Airdots 3 true wireless bluetooth earphones continues the design of previous generations in appearance, and is relatively simple. The earphones and charging case are small in size, and the new color scheme is adopted, and the overall texture has been enhanced. The charging case has upgraded the charging interface, and has a quick pairing button on the inside, which is more convenient to use; the earphones hardware has also been greatly upgraded, which is more cost-effective among products at the same price.
In terms of internal circuits, the charging case inputs power through the USB Type-C interface, and there are TVS and self-recovery fuses for input overvoltage and overcurrent protection; CHIPSEA MCU is responsible for charging and discharging management, battery power management, earphones communication and other charging case control functions; LPS The LP6260 synchronous boost converter is used to boost the battery output to charge the earphones; the soft pack battery has a capacity of 610mAh, and the charging case has a Hall element to realize the earphones’s open-and-connect function.
In the earphone part, Redmi Airdots 3 is equipped with Qualcomm QCC3040 Bluetooth audio SoC, supports Qualcomm aptX Adaptive codec, supports Bluetooth 5.2; soft pack battery capacity 43mAh; earphone adopts capacitive touch solution, infrared optical sensor for in-ear detection function, single MEMS silicon microphones are used for call pickup, and the hybrid driver enhances voice performance.
This time, Redmi AirDots 3 has been upgraded significantly, and the price has also increased. In terms of product positioning, it does not conflict with Xiaomi’s current Redmi AirDots 2 and Xiaomi True Wireless Bluetooth earphones Air2 SE. It is expected to promote further sales of Xiaomi True Wireless Headphones increase.