What is CMOS Technology?
When we talk about CMOS and NMOS in electronic circuits, we’re discussing two key types of logic families. CMOS stands for Complementary Metal-Oxide-Semiconductor, and it uses both PMOS and NMOS transistors, whereas NMOS stands for N-channel Metal-Oxide Semiconductor and relies solely on FETs.
You’ll find CMOS technology preferred over NMOS for designing embedded systems, and here’s why: CMOS can handle both logic 0 and 1, making it versatile, while NMOS can only manage logic 1 (VDD). In NMOS, the output voltage after it passes through the gate is VDD minus the threshold voltage (Vt). CMOS, however, is chosen widely because it effectively propagates both logic levels.
In CMOS logic gates, a combination of n-type MOSFETs and p-type MOSFETs is used. The n-type MOSFETs create a pull-down network between the low-voltage power supply rail and the output, while the p-type MOSFETs form a pull-up network between the high-voltage rail and the output. When the gates of both types of transistors are connected to the same input, the p-type MOSFET will be on when the n-type MOSFET is off, and vice versa.
Both CMOS and NMOS technologies are used in digital logic circuits, static RAM, microprocessors, data converters, image sensors, and other electronic devices. However, CMOS technology is preferred over NMOS due to its superior features such as low static power consumption, resistance to noise, energy efficiency, and absence of heat generation. Though CMOS technology may be more expensive, its complex composition makes it difficult for unauthorized production.
In conclusion, CMOS technology is highly suitable for designing embedded systems due to its advantages. If you have any further questions or need a better understanding, please feel free to ask.