The IC SK6211 shown in the above image is a controller which facilitates the data communication between the PC/Laptop and the flash memory (EEPROM) of the pen drive. It is fully compatible with USB 2.0 protocols and USB Mass storage class V1.0 specification. The devices like memory card, hard disk, pen drive etc with high data storage capacity fall under the category of Mass Storage Devices. In order to communicate data with devices falling under this category the USB has defined a set of protocols. The operating system provides inbuilt libraries to handle such devices thereby preventing the need of any external drivers to be installed before using these devices. This controller IC can interface with all kind of NAND EEPROM.