Electrical Engineering ⇒ Topic : Depletion Enhancement MOSFET

Depletion Enhancement MOSFET

Figure (a) shows a depletion enhancement MOSFET. The construction is similar to that of enhancement mode MOSFET. The main difference is that a lightly doped N-type channel has been introduced between the two heavily doped source and drain blocks. When drain is made positive with respect to the source, a drain current will flow even with zero gate potential. If the gate is made negative with respect to the source, a depletion region is formed and the channel resistance is increased. This device is known as depletion mode MOSFET

                     Figure (a) N-channel depletion and enhancement MOSFET.

The drain and transfer characteristics of a depletion enhancement MOSFET is shown in Figures 1 (a) and 1 (b), respectively.

Figure (1) Drain and transfer characteristics for depletion and enhancement NMOS.

The circuit symbol for N-channel and P-channel depletion enhancement MOS has been shown in Figures 2 (a) and 2(b), respectively

                                      Figure (2) Symbol for N- and P-channel depletion MOS.