Environmental Engineering Reference
In-Depth Information
the output resistance is
It is apparent that resistance has increased compared to the pure CX
configuration. In particular, for MOS transistors the expression simplifies to
Note that the body effect contributes to the output resistance growth. For
bipolar devices we find the well-known result given in (2.11c), evaluated
assuming resistance
lower than
which tends to if is greater than
To determine the voltage and current gain of the CX configuration, we
make use of the
Norton
equivalent at the output of the circuit, as shown in
Fig. 2.7a. The expression of the Norton resistance is exactly the same as
given in (2.11). Then we only have to calculate the short-circuit output
current. We prefer to perform this calculation in two steps:
