SRAM Full Form

What is SRAM?

SRAM refers to Static Random Access Memory which consists of bistable circuits which have 4 to 6 transistors (M1, M2, M3, M4, M5, M6) and a flip flop. It helps in the memory to preserve or keep the bits of data. It provides fast data access. The data stored in SRAM deletes the data when the supply of power is removed i.e. it has a memory of volatile nature. It is used typically to store the cache and CPU’s internal registers. It is made up of metal-oxide-semiconductor field-effect transistors (MOSFETs), therefore it is also known as the 6T SRAM cell. It is used in electronic devices, microprocessors and general computing applications. It has 3 states: standby (idle circuit), writing (contents updating), and reading (the data is solicited). It has a semiconductor form of memory. SRAM in microcontrollers is the integration of Random Access Memory and cache memory for registers storage as well as in microprocessors as the elementary cache. The access time that a SRAM supports is 10 seconds.

History of SRAM

In 1963, first SRAM (bipolar semiconductor) was invented at Fairchild Semiconductor by Robert Norman and in 1964, John Schmidt was the engineer who invented SRAM at Fairchild Semiconductor. At that time the SRAM was a 64-bits p channel metal oxide semiconductor. SRAM since 1959 plays a major role in development of Complementary metal-oxide-semiconductor. IBM workers, Eugene Schlig and Arnold Farber developed a memory cell of hard wire by using tunnel diode latch and transistors and further the latch was replaced by two resistors and two transistors and this cell came to be known as Farber-Schlig cell. Benjamin Agusta with his teammates in 1965 developed a 16-bit silicon memory chip having 4 diodes, 80 transistors and 64 resistors at IBM which was based on the cell of Farber-Schlig. In 1969, the first Intel 1101 SRAM chip of 256 bit was released by Intel. Ceramic plastics are used in manufacturing of early SRAM chips. Nowadays, for better and fast processing of computers these are directly integrated with the Central Processing Unit (CPU).

Types of SRAM

The types of SRAM are as follows:

1. Non-volatile SRAM: It is used in aerospace, medical, networking and many more and protects the data critically even when supply of power is cut.

2. Pseudo SRAM: They are cost and density friendly than that of true SRAM. It has a circuit of self refreshing and storage cores. An example of pseudo SRAM is Cypress Semiconductor. Its performance is higher than the original SRAM.

• By transistor type: The example of by transistor type of SRAM is Metal-oxide-semiconductor field-effect transistors (MOSFETs) and Bipolar junction transistors
• By flip-flop type: Examples are: Ternary and Binary SRAM
• By function: It consists of two types of SRAMs and they are; Asynchronous SRAM and Synchronous SRAM
• By feature: It is of four types and they are: DDR SRAM, Zero Bus Turnaround (ZBT), Quad Data Rate SRAM and Synchronous Burst SRAM

Characteristics of SRAM

The characteristics of SRAM are:

• Statical storage of data in its memory
• It is used to store cache
• To store bits it uses a flip flop with 4-6 transistors
• It provides good readability, reliability and stability of data
• It exhibits remanence of data

Advantages of SRAM

The advantages of SRAM are:

• Its access is fast
• It helps in performing the operations like writing and reading
• It provides random data access
• It stored data statically so doesn’t require data refreshing
• It uses less power than Dynamic Random Access Memory (DRAM) so it uses medium consumption of power

Disadvantages of SRAM

The disadvantages of SRAM are:

• Expensive
• It has a volatile natured memory
• It stores less data
• They have complex designs with bigger sizes than DRAM
• It doesn’t not allow the program to be refreshed

Conclusion

SRAM stands for Static Random Access Memory is a semiconductor which stores the bits of data by flip flop circuit. It possesses the remanence of the data and has volatile type of memory. It provides reliability, simplicity, low power consumption and better performance but it is costly. It is used to protect the cache memory and also in computer workstations. It consists of 3 states and they are; write, read and standby.