Complementary CMOS Inverter - DC Characteristics
A complementary CMOS inverter is implemented as the series connection of a p-device and an n-device, as shown in Figure 2.10. Note that the source and the substrate (body) of the p -device is tied to the VDD rail, while the source and the substrate of the n-device are connected to the ground bus. Thus, the devices do not suffer from any body effect. To derive the DC transfer characteristics for the CMOS inverter, which depicts the variation of the output voltage (Vout) as a function of the input voltage (Vin), one can identify five following regions of operation for the n -transistor and p -transistor.
Figure 2.10 A CMOS inverter shown with substrate Connections