USB 2.0 expansion dock

The circuit uses the SL2.1A chip and is designed according to the datasheet. However, there is no filtering at the input. A 10μF capacitor can be added for filtering if needed.
When designing the PCB, practicality wasn't considered because it was for testing purposes. A 49s crystal oscillator was used, and the two filter capacitors were placed on the bottom layer. If practicality is required, the crystal oscillator can be changed to a 3215 package and placed slightly away from the board edge, while the filter capacitors are placed on the top layer.
For impedance matching, LCSC's impedance calculation tool was used. Although this board isn't very sophisticated, it's better to be safe.
The docking station has been verified and works, but it hasn't been speed-tested. It might not be recognized immediately after plugging it in; you need to wait a while for it to install the driver.
Below is the schematic from the datasheet:
 
(January 2, 2024)
Recently, I had some free time and made some minor modifications, mainly changing the DM/DP to differential routing and slightly removing the Type-C pull-down resistors from the interface for easier soldering.