Some time ago, I bought these Bluetooth TWS headphones on Aliexpress, for my personal use. Unfortunately the size wasn't comfortable for me, they just keep popping out of my ears. Before saying goodbye, let's see what's inside ...
Let's start with the charging case:
The case is responsible for storing and, at the same time, recharging the internal battery of each earphone. It contains a small PCB with a charge controller IC, a 450mAh (??, unmarked) battery, and 2 pairs of "pogo-pins" that make contact with each earphone for charging. If we look at the back of the PCB, we can see that it was designed for different combinations of components, depending on the need.
MP3402C - Bluetooth headset charge controller IC (PDF, chinese)
Then we proceed to open one of the earphones...
Very carefully, until dissassembly is complete.
The level of miniaturization is incredible: the 40mAh battery is smaller than a fingernail, and the PCB is only 5mm wide. We can see the antenna is of the "chip" type, not printed on the same circuit (better signal in theory). With the help of a microscope we can identify the main SOC:
DCFB14D7B - SOC Bluetooth, unknown (no info)
I was unable to find information about this SOC on internet. The seller says that the product is Bluetooth 5.0, and my cellphone is 4.1 therefore I cannot corroborate if it is 5.0 or not... What baffled me though, is the chip logo: it looks suspiciously similar to ABell, a Chinese manufacturer of relatively good radio transmitters and related gear.
If we look at their website, we can't find any info on IC manufacturing, only assembled products ... Are we facing plagiarism, or they make SOCs but do not mention/advertise it? For example, Sunplus/GeneralPlus are well known for having a business structure that often allows you to identify a chip as their own, but prevents you from finding out exactly which filial it comes from. This may be the case, maybe not.
For now, all that remains is to reassemble everything, and give it to someone with bigger ears :)