555 Timer/oscillator

EBook Description: The 555 timer IC was first introduced around 1971 by the Signetics Corporation as the SE555/NE555 and was called 'The IC Time Machine' and was also the very first and only commercial timer ic available. It provided circuit designers and hobby tinkerers with a relatively cheap, stable, and user-friendly integrated circuit for both monostable and astable applications.

Even though this book is lengthy and takes time to complete reading but is very helpful since its covered all the points of Digital Circuits in a simple and understandable way.

Learn About LED's(Light Emitting Diodes

This book contains each and every information about LED right from how it is produced how light is formed till its applications....

How Computers Work

Computers are the most complex machines that have ever been created. Very few people really know how they work. This book will tell you how they work and no technical knowledge is required. It explains the operation of a simple, but fully functional, computer in complete detail.

ASICs(Application Specific Integrated Circuits)

The semiconductor industry has evolved from the first ICs of the early 1970s and matured rapidly since then. Early small-scale integration ( SSI ) ICs contained a few (1 to 10) logic gates�NAND gates, NOR gates, and so on�amounting to a few tens of transistors. The era of medium-scale integration ( MSI ) increased the range of integrated logic available to counters and similar, larger scale, logic functions. The era of large-scale integration ( LSI ) packed even larger logic functions, such as the first microprocessors, into a single chip.

CMOS LOGIC

A CMOS transistor (or device) has four terminals: gate , source , drain , and a fourth terminal that we shall ignore until the next section. A CMOS transistor is a switch. The switch must be conducting or on to allow current to flow between the source and drain terminals (using open and closed for switches is confusing�for the same reason we say a tap is on and not that it is closed ). The transistor source and drain terminals are equivalent as far as digital signals are concerned

ASIC LIBRARY

Once we have decided to use an ASIC design style�using predefined and precharacterized cells from a library�we need to design or buy a cell library. Even though it is not necessary a knowledge of ASIC library design makes it easier to use library cells effectively.

PROGRAMMABLE ASICs

There are two types of programmable ASICs: programmable logic devices (PLDs) and field-programmable gate arrays (FPGAs). The distinction between the two is blurred. The only real difference is their heritage

PROGRAMMABLE ASIC LOGIC CELLS

All programmable ASICs or FPGAs contain a basic logic cell replicated in a regular array across the chip (analogous to a base cell in an MGA). There are the following three different types of basic logic cells: (1) multiplexer based, (2) look-up table based, and (3) programmable array logic. The choice among these depends on the programming technology.

PROGRAMMABLE ASIC I/O CELLS

All programmable ASICs contain some type of input/output cell ( I/O cell ). These I/O cells handle driving logic signals off-chip, receiving and conditioning external inputs, as well as handling such things as electrostatic protection. This chapter explains the different types of I/O cells that are used in programmable ASICs and their functions.

PROGRAMMABLE ASIC INTERCONNECT

All FPGAs contain some type of programmable interconnect . The structure and complexity of the interconnect is largely determined by the programming technology and the architecture of the basic logic cell. The raw material that we have to work with in building the interconnect is aluminum-based metallization, which has a sheet resistance of approximately 50 m W /square and a line capacitance of 0.2 pFcm �1 .

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