Why do TWS earphones need 0402 patch fuses?

Why do TWS earphones prefer 0402 patch fuses inside?
In TWS earphones, a highly integrated precision device, the selection of each component is crucial. Among them, the 0402 patch fuse plays an indispensable role as a tiny circuit protection component. So, why do designers choose it so unanimously?
The primary reason is the ultimate space saving. The internal space of TWS earphones can be described as "every inch of land is precious", and the motherboard area is compressed to a very small size. The packaging size of the 0402 patch fuse is only 1.0mm x 0.5mm. This small volume allows it to be easily embedded in dense circuit board layouts, occupying almost no valuable space and leaving more space for core components such as batteries, chips, and speakers.
Secondly, there is a crucial overcurrent protection function. Headphones may generate abnormal overcurrent during charging, data transmission, or when encountering circuit faults. At this point, the 0402 patch fuse will quickly melt, cutting off the circuit and effectively preventing potential more serious damage. This layer of protection is like a loyal guardian, guarding the precious Bluetooth control chip, power management chip, etc. inside, avoiding damage due to current surges, and improving the overall reliability and safety of the product.
Furthermore, it adapts to modern production processes. TWS earphones are generally produced using fully automatic surface mount machines, and the 0402 surface mount fuse, as a standard surface mount component, is very suitable for this high-precision automated mounting process. This not only ensures production efficiency, but also ensures consistency and reliability of welding, meeting the needs of large-scale production.
Therefore, it is precisely due to its comprehensive advantages in space occupation, safety protection, and production adaptability that 0402 patch fuses have become a small but crucial choice in the internal circuit design of TWS earphones. It ensures that users can enjoy wireless convenience while also having a stable and secure user experience.