The main purpose of SDRAM is to store data. Data is stored as either a “1” or a “0”, and these 1s or 0s are known as a “bit”. Every bit is stored in one memory cell, but the memory cell (or the bits) need to be refreshed periodically. “Synchronous” means all the signals are synchronized to the clock signal. “Dynamic” implies the memory array has to be dynamically refreshed periodically; if not, the stored information is lost. “Random Access” means access to be any part of the memory array. The SDRAM is a volatile memory, which means data will be lost forever after power off. Products under the SDRAM family include a group of devices differentiated by interface, voltage, speed, power consumption, and package types. Different groups are SDR, DDR1/2/3/4. Low power SDRAM is often referred to as Mobile SDRAM. Mobile SDRAM's primary advantage is lower power consumption during stand-by mode, making these devices ideal for portable or battery powered applications.