Digital circuits are invariably constructed with integrated circuits. An integrated circuit is a small silicon semiconductor crystal, called a chip containing electrical components such as transistors, diodes, resistors, and capacitors.
The various components are interconnected inside the chip to form an electronic circuit. The chip is mounted on a metal or plastic package, and connections are welded to external pins to form the IC.
Why Are Integrated Circuits used?
Integrated circuits are very small electronic circuits which were built to perform a particular function made of active and passive components such as transistors, diodes, resistors, capacitors etc…
And these are sometimes called a chip or microchip, is a semiconductor wafer on which thousands or millions of tiny resistors or capacitors or transistors will be fabricated.
Integrated digital logic families will have either NAND or NOR gate is a logic gate.
Because NAND and NOR gates are universal gates and these will help the IC to perform efficiently as well as it will make them a smaller size. With the help of NAND and NOR representation, these ICs will cost little lower than other gates representation because any gates can be represented by NAND and NOR gate.
TTL – Transistor-Transistor Logic
TTL has an extensive list of digital functions and is currently the most popular logic family. Which has been built from bipolar junction transistors (BJTs) and resistors?
The term transistor-transistor is because both logic function and amplification is done by the transistor.
Using TTL logic families, many logic gates can be fabricated in a single integrated circuit. For logic gate built using TTL logic families, the input is given to the emitters of the input transistor.
ECL – Emitter Coupled Logic
ECL is used in systems requiring high-speed operations. This logic family will be integrated for high-speed operations and integrated circuit will be a bipolar transistor logic family.
ECL uses an overdriven BJT (bipolar junction transistors) differential amplifier with single-ended input and limited emitter current to avoid the saturated region of operation and it’s slow to turn off behaviour.
MOS – Metal-oxide semiconductor
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET). It has an insulated gate, whose voltage determines the conductivity of the device.
CMOS – Complementary Metal-oxide Semiconductor
CMOS is used in systems requiring low power consumption. Mostly CMOS technology is used in microprocessors, microcontrollers, or even on static RAM and other digital logic circuits as well as devices.
CMOS technology is also used for several analog circuits such as image sensors (CMOS sensor), data converters, and highly integrated transceivers for many types of communication.
I2L – Integrated-Injection Logic
Integrated injection logic is a class of digital circuits built with multiple collector bipolar junction transistors (BJT). It can also be used in devices like which consume lower power. Most effectively it can be used in VLSI chips.
Although the logic voltage levels are very close (High: 0.7V, Low: 0.2V), I2L has high noise immunity because it operates by current instead of voltage. It is sometimes also known as merged transistor logic.