Both were mentioned in reply #8. Yes, different companies manufacture them.
Other companies are also selling dedicated USB/Serial adapter chips, such as Cypress and Prolific.
You may not have received drivers, but I did. Maybe I just got lucky with the seller I selected. Times change, not sure I could tell you who that was anymore,altho it was a BATE make board that had DTR broken out to a thruhole for easy access.