Can you be more clear what the application really is?

- No there not any single chip solutions that offer MCU capability with RS232 signalling on one side and USB signalling on the other side.

- There are plenty of MCUs that offer USB on one side and UART async serial on the other side.

- To use the above type MCUs with RS232 signalling requires that the UART side of the MCU be buffered through a level shifter/inverter type component such as the MAX232 or a plethora of similar chips.

If your need is to simply translate a virtual Comm port from inside the PC out through USB to a RS232 serial port then there are dedicated parts that do that job. The one that I've used the most is from FTDI and called the FT232R. The FTDI chip must also be used with a companion MAX3243 or similar type part to achieve the RS232 signalling levels for the serial port.

Michael Karas