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NMOS AND-by-default logic can produce unusual glitches or buggy behavior in NMOS components, such as the 6502 "illegal opcodes" which are absent in CMOS 6502s. In some cases such as Commodore's VIC-II chip, the bugs present in the chip's logic were extensively exploited by programmers for graphics effects.
CMOS inverter (a NOT logic gate). Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss ", / s iː m ɑː s /, /-ɒ s /) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. [1]
The first CMOS family of logic integrated circuits was introduced by RCA as CD4000 COS/MOS, the 4000 series, in 1968. Initially CMOS logic was slower than LS-TTL. However, because the logic thresholds of CMOS were proportional to the power supply voltage, CMOS devices were well-adapted to battery-operated systems with simple power supplies.
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 V negative (the drain, by comparison, is more positive than the source in NMOS).
MOSFET (PMOS and NMOS) demonstrations Date Channel length Oxide thickness [1] MOSFET logic Researcher(s) Organization Ref; June 1960: 20,000 nm: 100 nm: PMOS: Mohamed M. Atalla, Dawon Kahng: Bell Telephone Laboratories [2] [3] NMOS: 10,000 nm: 100 nm: PMOS Mohamed M. Atalla, Dawon Kahng: Bell Telephone Laboratories [4] NMOS May 1965: 8,000 nm ...
There are three symbols for NOR gates: the American (ANSI or 'military') symbol and the IEC ('European' or 'rectangular') symbol, as well as the deprecated DIN symbol. For more information see Logic Gate Symbols. The ANSI symbol for the NOR gate is a standard OR gate with an inversion bubble connected.
Current mode logic (CML), or source-coupled logic (SCL), is a digital design style used both for logic gates and for board-level digital signaling of digital data. The basic principle of CML is that current from a constant current generator is steered between two alternate paths depending on whether a logic zero or logic one is being represented.
The MOS logic family includes PMOS logic, NMOS logic, complementary MOS (CMOS), and BiCMOS (bipolar CMOS). Current-mode logic: CML: Uses transistors to perform logic but biasing is from constant current sources to prevent saturation and allow extremely fast switching. Has high noise immunity despite fairly low logic levels. Quantum-dot cellular ...