CP210x USB bridge selection
Silicon Labs CP210x devices connect USB to one or more logic-level UART ports. Select the exact bridge before reusing a board footprint or connector.
Identify the bridge
| Part | Key difference |
|---|---|
| CP2102 / CP2109 | Classic QFN-28 bridge. Confirm the use of pin 18, which is VPP on CP2109. |
| CP2102N | Different QFN options. The Silicon Labs porting guide maps power and UART pins when replacing a classic part. |
| CP2105 / CP2108 | Multi-UART bridges. Match each channel and modem signal to its own package table. |
Before bring-up
- Identify the full marking before using a board pin diagram.
- After the USB device enumerates, check its port identity and verify a UART loopback with flow control disabled.
Part and package guides
- CP2102 pinout and connection guide· Original CP2102 QFN-28 layout and bus-powered connection.
Manufacturer documents
- Silicon Labs classic USB bridges· Device comparison and documentation.
- Silicon Labs AN976 · CP2102N migration· Package-by-package migration from single-interface classic parts.