Static random access memory doesn’t require a refresh signal like DRAM does hence called static. The chips are more complex and are thus more expensive. SRAM is still volatile as data is lost when the memory is not powered. However, they are faster. DRAM access times come in at 60 nanoseconds (ns) or more; SRAM has access times as fast as 10ns. SRAM is often used for cache memory and is used in quantities of few KB or less. They are of two types, which are
Non-volatile SRAM – They save the data when the power supply is lost, ensuring preservation of critical information. They are used in networking, aerospace, and medical for preservation of data and where batteries are impractical.
Asynchronous SRAM – They are available from 4 Kb to 32 Mb and are used as main memory for small cache-less embedded processors used in switches and routers, IP-Phones, IC-Testers, DSLAM Cards, to Automotive Electronics.