Environmental Engineering Reference
In-Depth Information
Of course, this is not the only possible model, more accurate models can
be developed in particular to better approximate the behavior of the device
for frequencies higher than its transition frequency. However, except for RF
circuits, the model in Fig. 2.10 is sufficiently adequate to allow frequency
behavior analysis and feedback amplifier compensation to be performed.
Moreover, in the following we shall neglect the effect of the capacitance
for simplicity, because it is not responsible for any substantial effect.
2.7.1 Common X Configuration
The AC schematic of the common X configuration is shown in Fig. 2.11 a
and the corresponding high-frequency small-signal model is depicted in Fig.
2.11b.
The circuit voltage gain transfer function can be written as
