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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.
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.
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]
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).
Alternatively, inverters can be constructed using two complementary transistors in a CMOS configuration. This configuration greatly reduces power consumption since one of the transistors is always off in both logic states. [5] Processing speed can also be improved due to the relatively low resistance compared to the NMOS-only or PMOS-only type ...
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 ...
In NMOS logic, the lower half of the CMOS circuit is used in combination with a load device or pull-up transistor (typically a depletion load or a dynamic load). AOI gates are similarly efficient in transistor–transistor logic (TTL). Examples. CMOS 4000-series logic family: CD4085B = dual 2-2 AOI gate [3] CD4086B = single expandable 2-2-2-2 ...
[8] [9] The transition from NMOS to CMOS technology resulted in the necessity of tightly coupled and fully 2D simulators for process and device simulations. This third generation of TCAD tools became critical to address the full complexity of twin-well CMOS technology (see Figure 3a), including issues of design rules and parasitic effects such ...