GL823K master control plus SMD SD mini U disk

An ultra-simple mini USB flash drive designed using GL823K SDIO master control and SMD SD card. In fact, it is essentially an SD card + card reader solution. Compared with the parallel port nand flash solution of conventional USB flash drives, the circuit is much simpler and has fewer components. The RC package is 0805/0603. It is easy to weld and does not require card opening steps. It is very suitable for beginners to reproduce.
 
The flash memory particles used in the test are Thunder Dragon's 512MB SLC NAND chip SD, which has a lifespan of up to 100,000 PE times, a reading speed of 20mb/s, and a writing speed of 7mb/s. The quality is not bad. They also have other capacity models of SMD SD with capacities from 128MB to 8GB, which are compatible with pads. You can also try SD from other companies.
 
Because SMD SD is mainly used in industrial control fields with high reliability requirements, the price is on the high side, especially large-capacity ones. Therefore, it is recommended to buy a small-capacity one for fun. This USB flash drive does not have much practicality and is only suitable for DIY learning.
 
The PCB adopts a 1.6mm double-layer design. The solder pad at the USB interface needs to be tinned to ensure good contact. The total thickness must usually exceed 2mm. (Because Jialichuang cannot print thicker PCBs for free)
The overall design size is very small, and the large via hole at the tail can be stringed on a keychain. I personally think it looks very good. The silk screen on the back can be replaced with any text or pattern to hold X. good.
 
 
The price of the main control is about one yuan, which is relatively cheap, but the quality of the main control chip bought on Taobao is not very reliable. Usually it is not recognized after soldering because the IC is bad. You can measure the 3V3 and PMOS voltages to judge. When I verified it, it was not recognized after soldering the first piece, and then I suspected false soldering and design errors. It was not until I changed to a good main control that it was immediately recognized.
 
Note that NAND flash chips are afraid of high temperatures, so the soldering temperature and time of SMD SD should not be too long. It is best to solder at the end.