The CP2105 is a highly-integrated USB-to-UART bridge controller that provides a simple solution for updating RS-232 designs to USB using a minimum number of components and PCB space. The CP2105 includes a USB 2.0 full-speed function controller, USB transceiver, oscillator, one-time programmable ROM and two asynchronous serial data buses (UART) with full modem control signals in a compact 4mm x 4mm 24-pin QFN package. The on-chip one-time programmable ROM may be used to customize the USB Vendor ID, Product ID, product description string, power descriptor, device release number and device serial number as desired for OEM applications. Royalty-free Virtual COM Port (VCP) device drivers provided by Silicon Labs allow a CP2105-based product to appear as two COM ports in PC applications. The CP2105 UART interface implements all RS-232 signals including control and handshaking, so existing system firmware does not need to be modified. The device also features a total of five GPIO signals that can be user-defined for status and control information. Support for I/O interface voltages down to 1.8V is provided via a VIO pin. Direct access driver support is also available through the Silicon Labs USBXpress driver set. See silabs.com for the latest application notes and product support information for the CP2105. An evaluation kit for the CP2105 (Part Number: CP2105EK) is available. It includes a CP2105-based USB-to-UART/RS-232 evaluation board, a complete set of VCP device drivers, USB and RS-232 cables and full documentation.