Static Random Access Memory (SRAM)

SRAM, or Static Random Access Memory, is a type of computer memory that stores data in a static form, meaning it does not require refreshing like dynamic RAM (DRAM). SRAM is commonly used in cache memory, as it provides faster access times compared to DRAM.

Structure of a SRAM Cell

Each cell of a static Random Access Memory contains 6 MOS transistors. These transistors are typically implemented using CMOS (Complementary Metal-Oxide-Semiconductor) technology. The transistors are arranged in a flip-flop circuit configuration, which allows the cell to store a single bit of data.

Explanation of MOS Transistors in a SRAM Cell

The 6 MOS transistors in a SRAM cell are used to implement the flip-flop circuit. The flip-flop consists of two cross-coupled inverters. Each inverter is made up of two MOS transistors, one PMOS (P-channel MOS) and one NMOS (N-channel MOS) transistor.

The PMOS transistor is connected between VDD (power supply voltage) and the output of the inverter. The NMOS transistor is connected between the output of the inverter and ground. The gates of these transistors are connected together, forming a feedback loop.

When the input to the flip-flop changes, it causes one of the transistors to turn on and the other to turn off. This changes the state of the flip-flop and stores the new data value. The data is maintained as long as power is supplied to the SRAM cell.

Advantages of Using MOS Transistors

The use of MOS transistors in SRAM cells provides several advantages:

1. Low power consumption: MOS transistors have low leakage current, resulting in lower power consumption compared to other transistor technologies.

2. High density: MOS transistors can be fabricated in a small area, allowing for high-density memory arrays.

3. Fast access times: MOS transistors can switch quickly, resulting in faster access times for reading and writing data.

4. Non-volatile storage: SRAM cells can retain data even when power is turned off, making them suitable for cache memory applications.

In conclusion, each cell of a static Random Access Memory contains 6 MOS transistors. These transistors are used to implement a flip-flop circuit, which stores a single bit of data. The use of MOS transistors provides advantages such as low power consumption, high density, and fast access times.