Radio Frequency Integrated Circuit Design - Webs

112 Radio Frequency Integrated Circuit Design
Figure 5.14 Inductor with dimensions.
Solution
We can start by estimating the inductance of the structure by using the formulas
in Section 5.11 and referring to Figure 5.9.
davg = 1
2 (D out + D in) = 1
(270 �m + 161 �m) = 215.5 �m
2
� = (D out − D in) (270 �m − 161 �m)
= = 0.253
(D out + D in) (270 �m + 161 �m)
L = 2.34� o
n 2 d avg
1 + 2.75�
= 2.34 � 4� × 10 −7 N
A 2
3 2 � 215.5 �m
1 + 2.75 � 0.253
= 3.36 nH
Next, let us estimate the oxide capacitance. First, the total length of the
inductor metal is 2.3 mm. Thus, the total capacitance through the oxide is