Digital Systems: Principles and Design

147Different Types of Logic Gates

6.8 NMOS

There are two types of MOSFETs, n-channel and p-channel. Circuits based on n-channel

MOSFETS are called NMOS circuits.

6.8.1 NMOS Circuit Connections and Working

Figure 6.10 shows a NMOS inverter. Enhancement mode or deletion mode n-channel

MOSFET T acts as an active pull up load (in place of R, which occupies larger silicon area).

An enhancement mode MOSFET T acts as a inverter and gives an output V

o

at F.

FIGURE 6.10 An NMOS inverter.

Figure 6.11(a) shows a two input NMOS NOR. A depletion mode n-channel MOSFET

T acts as an active pull up load (in place of R, which occupies larger silicon area). Two

enhancement-mode ...