Microprocessor devices. Lecture 3

Contents of the lecture

Definitions
Elementary SRAM Cell
SRAM organization
SRAM operation

What does RAM mean?

This term has two different meanings:
Random Accessed

Static RAM (SRAM)

SRAM is a type of semiconductor memory that uses

The elementary SRAM memory cell

If the output of a non-inverting amplifier

Building the elementary SRAM memory cell

Amplifying transistor stages are inverting; so,

Drawing the elementary memory cell

When this circuit represents a latch, it

Controlling the elementary memory cell

In an SRAM, access to the memory

Operation modes of the memory cell…

The SRAM cell has three different

Standby mode…

If the word line is not active, the access switches disconnect the cell

Writing “1” to the memory cell

To write a “1” into the

Keeping the “1” in the memory cell…

…The word line becomes not

Writing “0” to the memory cell

To write a “0” into the

Keeping the “0” in the memory cell…

…The word line becomes not

Reading data from the memory cell

To read data from the SRAM

Implementation: 4-transistor memory cell…

The core of the memory cell can be

6-transistor memory cell

The RMOS inverters continuously dissipate power. The better solution

SRAM organization

SRAM memory cells are organized in a form of a

SRAM matrix of cells

SRAM operation

SRAMs require a few control signals:
CS (chip select) –

READ operation