A low-profile Universal-Serial-Bus (USB) assembly includes a modular USB core component that is mounted into a swivel casing. The modular USB core component includes a PCBA in which all passive components and unpackaged IC chips are attached to a single side of a PCB opposite to the metal contacts. The IC chips (e.g., USB controller, flash memory) are attached to the PCB by wire bonding or other chip-on-board (COB) technique. The passive components are attached by conventional surface mount technology (SMT) techniques. The swivel casing includes a holder that is pivotably mounted into an external housing by way of a pivot pin. The pivot pin is either a separate structure that is inserted into holes formed in the holder and housing, or is integrally formed on the holder.