|
Depletion-mode
In field-effect transistors (FETs), depletion mode and enhancement mode are two major transistor types, corresponding to whether the transistor is in an on state or an off state at zero gate–source voltage. Enhancement-mode MOSFETs (metal–oxide–semiconductor FETs) are the common switching elements in most integrated circuits. These devices are off at zero gate–source voltage. NMOS can be turned on by pulling the gate voltage higher than the source voltage, PMOS can be turned on by pulling the gate voltage lower than the source voltage. In most circuits, this means pulling an enhancement-mode MOSFET's gate voltage towards its drain voltage turns it on. In a depletion-mode MOSFET, the device is normally on at zero gate–source voltage. Such devices are used as load "resistors" in logic circuits (in depletion-load NMOS logic, for example). For N-type depletion-load devices, the threshold voltage might be about −3 V, so it could be turned off by pulling the gate 3&nb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depletion-load NMOS Logic
In integrated circuits, depletion-load NMOS is a form of digital logic family that uses only a single power supply voltage, unlike earlier NMOS logic, NMOS (n-type metal-oxide semiconductor) logic families that needed multiple power supply voltages. Although manufacturing these integrated circuits required additional processing steps, improved switching speed and the elimination of the extra power supply made this logic family the preferred choice for many microprocessors and other logic elements. Depletion and enhancement modes, Depletion-mode n-type MOSFETs as load transistors allow single voltage operation and achieve greater speed than possible with enhancement-load devices alone. This is partly because the depletion-mode MOSFETs can be a better current source approximation than the simpler enhancement-mode transistor can, especially when no extra voltage is available (one of the reasons early PMOS and NMOS chips demanded several voltages). The inclusion of depletion-mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FET Comparison
The field-effect transistor (FET) is a type of transistor that uses an electric field to control the current through a semiconductor. It comes in two types: junction FET (JFET) and metal-oxide-semiconductor FET (MOSFET). FETs have three terminals: ''source'', ''gate'', and ''drain''. FETs control the current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source. FETs are also known as unipolar transistors since they involve single-carrier-type operation. That is, FETs use either electrons (n-channel) or holes (p-channel) as charge carriers in their operation, but not both. Many different types of field effect transistors exist. Field effect transistors generally display very high input impedance at low frequencies. The most widely used field-effect transistor is the MOSFET (metal–oxide–semiconductor field-effect transistor). History The concept of a field-effect transistor (FET) was first patented by the Austr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor Types
A transistor is a semiconductor device used to amplify or switch electrical signals and power. It is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more in miniature form are found embedded in integrated circuits. Because transistors are the key active components in practically all modern electronics, many people consider them one of the 20th century's greatest inventions. Physicist Julius Edgar Lilienfeld proposed the concept of a field-effect transistor (FET) in 1925, but it was not possible to construct a working device at that time. The first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zilog Z80
The Zilog Z80 is an 8-bit computing, 8-bit microprocessor designed by Zilog that played an important role in the evolution of early personal computing. Launched in 1976, it was designed to be Backward compatibility, software-compatible with the Intel 8080, offering a compelling alternative due to its better Integrated circuit, integration and increased performance. Along with the 8080's seven Processor register, registers and flags register, the Z80 introduced an alternate register set, two 16-bit index registers, and additional instructions, including bit manipulation and block copy/search. Originally intended for use in embedded systems like the 8080, the Z80's combination of compatibility, affordability, and superior performance led to widespread adoption in video game systems and home computers throughout the late 1970s and early 1980s, helping to fuel the personal computing revolution. The Z80 was used in iconic products such as the Osborne 1, TRS-80, Radio Shack TRS-80, Col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JFET
The junction field-effect transistor (JFET) is one of the simplest types of field-effect transistor. JFETs are three-terminal semiconductor devices that can be used as electronically controlled switches or resistors, or to build amplifiers. Unlike bipolar junction transistors, JFETs are exclusively voltage-controlled in that they do not need a biasing current. Electric charge flows through a semiconducting channel between ''source'' and ''drain'' terminals. By applying a reverse bias voltage to a ''gate'' terminal, the channel is '' pinched'', so that the electric current is impeded or switched off completely. A JFET is usually conducting when there is zero voltage between its gate and source terminals. If a potential difference of the proper polarity is applied between its gate and source terminals, the JFET will be more resistive to current flow, which means less current would flow in the channel between the source and drain terminals. JFETs are sometimes referred to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germanium
Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically similar to silicon. Like silicon, germanium naturally Chemical reaction, reacts and forms complexes with oxygen in nature. Because it seldom appears in high concentration, germanium was found comparatively late in the Timeline of chemical element discoveries, discovery of the elements. Germanium ranks 50th Abundance of elements in Earth's crust, in abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev Mendeleev's predicted elements, predicted its existence and some of its Chemical property, properties from its position on his periodic table, and called the element ekasilicon. On February 6, 1886, Clemens Winkler at Freiberg University found the new element, along with silver and sulfur, in the mineral argyrodite. Winkle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium Arsenide
Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monolithic microwave integrated circuits, infrared light-emitting diodes, laser diodes, solar cells and optical windows. GaAs is often used as a substrate material for the epitaxial growth of other III-V semiconductors, including indium gallium arsenide, aluminum gallium arsenide and others. History Gallium arsenide was first synthesized and studied by Victor Goldschmidt in 1926 by passing arsenic vapors mixed with hydrogen over gallium(III) oxide at 600 °C. The semiconductor properties of GaAs and other Compound semiconductor, III-V compounds were patented by Heinrich Welker at Siemens-Schuckert in 1951 and described in a 1952 publication. Commercial production of its monocrystals commenced in 1954, and more studies followed in the 195 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power–delay Product
In digital electronics, the power–delay product (PDP) is a figure of merit correlated with the energy efficiency of a logic gate or logic family. Also known as switching energy, it is the product of power consumption ''P'' (averaged over a switching event) times the input–output delay or duration of the switching event ''D''. It has the dimension of energy and measures the energy consumed per switching event. In a CMOS circuit the switching energy and thus the PDP for a 0-to-1-to-0 computation cycle is CL·VDD2. Therefore, lowering the supply voltage VDD lowers the PDP. Energy-efficient circuits with a low PDP may also be performing very slowly, thus energy–delay product (EDP), the product of ''E'' and ''D'' (or ''P'' and ''D''2), is sometimes a preferable metric. In CMOS circuits the delay is inversely proportional to the supply voltage VDD and hence EDP is proportional to VDD. Consequently, lowering VDD also benefits EDP. See also * Voltage scaling In computer archi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Logic (digital Logic)
In integrated circuit design, dynamic logic (or sometimes clocked logic) is a design methodology in combinational logic circuits, particularly those implemented in MOSFET, metal–oxide–semiconductor (MOS) technology. It is distinguished from the so-called static logic by exploiting temporary storage of information in stray capacitance, stray and gate capacitances. It was popular in the 1970s and has seen a recent resurgence in the design of high-speed digital electronics, particularly central processing units (CPUs). Dynamic logic circuits are usually faster than static counterparts and require less surface area, but are more difficult to design. Dynamic logic has a higher average rate of voltage transitions than static logic, but the CPU power dissipation, capacitive loads being transitioned are smaller so the overall power consumption of dynamic logic may be higher or lower depending on various tradeoffs. When referring to a particular logic family, the dynamic adjective u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 4004
The Intel 4004 was part of the 4 chip MCS-4 micro computer set, released by the Intel, Intel Corporation in November 1971; the 4004 being part of the first commercially marketed microprocessor chipset, and the first in a long line of List of Intel processors, Intel central processing units (CPUs). Priced at , the chip marked both a technological and economic milestone in computing. The 4-bit computing, 4-bit 4004 CPU was the first significant commercial example of large-scale integration, showcasing the abilities of the Self-aligned gate, MOS silicon gate technology (SGT). Compared to the existing technology, SGT enabled twice the transistor density and five times the operating speed, making future single-chip CPUs feasible. The MCS-4 chip set design served as a model on how to use SGT for complex logic and memory circuits, accelerating the adoption of SGT by the world's semiconductor industry. The project originated in 1969 when Busicom, Busicom Corp. commissioned Intel to de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
