Redmi AirDots 2 true wireless bluetooth earphones teardown

Not long ago, an analysis agency released the 2020 Q1 global smart audio equipment (earphones/speakers) total shipment data report, showing that Redmi’s TWS true wireless earphones sales are second only to Apple and Samsung, ranking third with 3.1 million positions, and market share The rate is 7% and remains stable. From the time point of view, it is the original Redmi AirDots product that drives sales, and the cost-effective route has attracted many consumers.

Today we are going to teardown the Redmi AirDots 2 true wireless bluetooth earphones. It maintains the same appearance as the previous two generations. It has a bean-shaped in-ear design. In terms of configuration, the earphones uses a new 7.2mm sound unit larger than the previous generation and a built-in bluetooth 5.0 chip. Support percussion control. Let’s take a look at the internal structure and components through disassembly~

01/ Redmi AirDots 2 charging case teardown

First, disassemble the charging case and pry open the charging cockpit to see the internal structure.

The battery is fixed on the shell by double-sided tape.

The charging case uses a T-shaped motherboard and is fixed on the inside of the charging cockpit with three screws.

Remove the screws to see the inner structure of the charging cockpit. There are 5 bar magnets on the inside of the charging cockpit, four of which are for attaching and fixing the earphones, and the upper one is for attaching the charging case cover.

Internal circuit of charging case.

The charging case uses the Micro-USB interface to input power, and the power management circuit is responsible for the charging and discharging of the battery.

A close-up of the Micro-USB interface female seat.

SGMICRO SGM4056 linear charging IC, built-in overvoltage protection, the highest withstand voltage is 26.5V, and has 6.8V overvoltage protection, which can save external overvoltage protection components.

XySemi XB5335A integrated lithium battery protection IC is used to protect the internal battery of the charging case from overcharge and overdischarge.

According to 52audio, there are already a large number of XySemi battery protection solutions for TWS earphones from brands such as QCY, Redmi, Meizu, Pemate, Sony Ericsson, Go Ask, Edifier, and Honor.

The wires are connected to the positive and negative poles of the battery, and there are insulation protection stickers on the outside.

The charging case uses a soft pack battery, model PL501340, with a capacity of 300mAh/1.11Wh and a rated voltage of 3.7V, which is the same as the previous generation.

SGMICRO SGM66051 high-efficiency synchronous rectification boost converter, boosts the current output by the built-in battery to charge the earphones, with a fixed output of 5.1V.

A close-up of the Pogo Pin charging the earphones, and the output is protected by TVS to prevent electrostatic breakdown.

A group photo of the charging cockpit disassembled.

02/ Redmi AirDots 2 earbuds teardown

Next, we will disassemble the earphone part. The earphone is a bean-type in-ear design, and there are physical button controls under the shell.

Inside the housing are the charging contacts and the L/R logo.

The call microphone pickup hole at the bottom of the earphones.

There is a fine dust-proof net at the sound hole to prevent foreign matter from entering.

The tuning hole at the sound hole.

Disassemble the earphones along the mold line, the structure of the motherboard + soft pack battery+speaker.

The internal structure of the earphones is displayed.

The internal layout of the left and right earphones is the same.

Take out the soft pack battery in the earphone, model: 541112, capacity: 0.16Wh, consistent with the previous generation.

In the layout of the sound cavity, between the two magnets that adsorb the charging box is a small plate of the charging contact, which is fixed by hot melt and glue. On the far left is the speaker unit, which is connected to the motherboard through a wire.

Take out the speaker unit.

The speaker unit size is about 5.4mm.

A close-up of the charging contacts of the earphones.

The external circuit of the motherboard is displayed.

Two LED indicators.

Screen printing MI5 K2G lithium battery protection IC.

The bluetooth chip has an external 40MHz clock crystal oscillator.

Jog button.

The earphones uses a PCB laminated bluetooth antenna to send and receive data.

On the back of the motherboard is the bluetooth master chip and related circuits. This time Redmi AirDots 2 uses a silk-screened XM2000 bluetooth audio SoC. According to 52audio, it was customized by Xiaomi in cooperation with a bluetooth chip factory.

The official advertised that this chip supports bluetooth 5.0, which optimizes the interconnection method of the left and right earphones, does not limit the main and auxiliary devices, and supports single and double ear use.

The XM2000 chip is about 3.85mm wide.

The XM2000 chip is about 5.73mm long.

MEMS silicon microphone used to pick up human voices during calls.

All components of Redmi AirDots 2.

03/ Summary

The appearance design of Redmi AirDots 2 is consistent with the previous two generations of products; from the disassembly of the hardware level, the main change of Redmi AirDots 2 is the application of a new bluetooth audio SoC.

The earphones charging case is still Micro-USB interface, built-in SGMICRO SGM4056 linear charging IC, supporting overvoltage protection, charging the charging case battery; XySemi XB5335A is responsible for the battery protection function, the charging case uses a soft pack battery with a capacity of 300mAh; the battery output current is SGMICRO SGM66051 boosts to charge the earphones.

The earphones is still controlled by buttons, and the battery capacity of 0.16Wh is about 43mAh the same as the previous generation. The earphones newly uses a bluetooth audio SoC model XM2000. Recently, Xiaomi has continuously invested in the semiconductor field. I wonder if it will pick up the self-developed chip again, starting with the bluetooth chip required for TWS earphones.

The market competition for TWS entry-level products is very fierce this year. 52audio has also been dismantled a lot recently, from appearance to hardware and functionality. The overall configuration of Redmi AirDots 2 is still at the price level, and the high sales may be more due to the brand.

Source: 52audio

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