Advantages and Disadvantages of NMOS Gates

The following are the advantages and disadvantages of NMOS gates.

Advantages of NMOS gates

1. The number of diffusions steps required is the lowest. Hence, cost per gate is the lowest.
2. Very low power dissipation (on the order of a few nW).
3. Power supply can be varied from 5 V to 15 V possible.
4. Only NMOS transistors are used, no isolation-islands are required. Hence, highest  packing density of all logic families. Suitable for VSLI, ULSI etc.

5. Large fan out capability (20 gates)
6. Very high noise-margin. Suitable for use in industrial atmosphere.
7. MOS circuits are used as capacitors. They can also be used as resistors.
8. MOS devices are used in charge-coupled devices (CCDs).

Disadvantages of NMOS gates

1. MOS transistors are also capacitors. Hence, speed of operation is lowest due to very high capacitive loading.
2. Large propagation delay per gate.
3. Higher power dissipation than CMOS gates.
4. This technology has not acquired as much popularity as the CMOS technology. CMOS, because of its lower power dissipation and higher speed of operation has replaced NMOS almost completely.

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