Memory device in mobile phone

A memory device for a mobile phone is provided. The memory device includes a flash memory for storing program data and user data; an interface circuit for copying program data stored in the flash memory according to whether data stored in the flash memory is valid; a first Random Access Memory (RAM) for providing an operation area to store and execute the copied program data; and a second RAM for storing data generated during the execution of program data, wherein the first and second RAMs are independent memories.