What is an SRAM?

SRAM (Static Random Access Memory) can retain the data bits in the memory till there is a power supply. The SRAM need not be refreshed periodically and can provide faster data access than the DRAM. It is usually used for any computer’s cache memory. It is more expensive than the DRAM.

The circuit generally has four transistors that are set up as two cross-coupled inverters. There are two stable states that are the "0" and "1" states. The SRAM can work at higher speeds than any DRAM and is expensive to produce due to its complex structure.

Types

The different types of SRAM are as follows:

• Pseudo SRAM: It uses the self-refresh circuit and has the DRAM storage core. They appear as a slower SRAM.
• Non-volatile SRAM: It can save critical information as it can save data when the power supply is lost.

According to the type of transistor, it can be classified into:

• MOSFET: They are commonly used and are of low power.
• Bipolar Junction Transistors: They are fast but utilise high power.

According to the features, they can be classified as:

• DDR SRAM: It has a single read/write port, is synchronous, and has a double data rate I/O.
• SyncBurst: It has synchronous burst write access to SRAM and increases the write operation to the SRAM.
• Zero Bus Turnaround: Turnaround for the ZBT SRAMs (i.e., latency between the read and write cycle) is zero.
• Quad Data Rate SRAM: It has distinct read and write ports, is synchronous, and has quadruple data rate I/O.

Applications

There are several scientific and industrial systems, embedded systems and automotive electronics that contain SRAM. In some cases, the SRAM in its dual-ported form can be used for real-time digital signal processing circuits. The SRAM is also used in routers, computers and workstations, internal CPU caches, etc.