Radio Frequency Integrated Circuit Design - Webs

The Use and Design of Passive Circuit Elements in IC Technologies
Figure 5.29 Three-dimensional drawing of a multilevel inductor.
The total capacitance can be found in C 2 in much the same way.
E C 2
1
=
2 C 2�V1 2 � 2
� 1
0
x 2 dx = 1 C 2
2 3 � 2 2 V 2 1
127
(5.27)
Note that V1/2 � x approximates the voltage across C 2 at any point along
the spiral.
Thus, the total capacitance is
C eq2 = C 1
3 � 2 2
C eq = C 1
3 + C 2
12
(5.28)
(5.29)
Note that the capacitor C 2 is of less importance than C 1. Thus, it would
be advantageous to space the two spirals far apart even if this means there is
more substrate capacitance (C 2). Note also that C 1 will have a low loss associated
with it, since it is not dissipating energy in the substrate.
5.22 Characterizing Transformers for Use in ICs
Traditionally, transformers are characterized by their S parameters. While correct,
this gives little directly applicable information about how the transformer will