Hardware Reference
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R
1
C
2
C
1
C
L
R
2
+
+
+
+
Y
-
+
-
V
0
Z
-
-
V
i
X
FDCCII
-
C
L
R
2
C
1
C
2
R
1
Fig. 12.24 AC-coupled LPF proposed by Alzaher et al. [
70
]
12.2.3 Filter Design Using FDCCII
The fully differential second generation CC (FDCCII) was advanced as a versatile
building block suitable for designing fully differential filters. However, with the
availability of extended versions of the FDCCII having as many as eight terminals
one may expect that it may be possible to use FDCCII to perform various analog
signal processing/ signal generation functions possibly with a bare minimum
passive components. That it is indeed so has been amply demonstrated by a number
of researchers see [
70
-
87
]. In the following we present some selected VM and CM
universal biquads using FDCCII which re-affirm the above assertion.
Alzaher-Elwan-Ismail fully-differential biquad Alzaher et al. [
70
] demon-
strated that a fully differential version of a classical Sallen-Key filter using FDCCII
exhibits low noise, high linearity and low power consumption, thereby making it
suitable for implementing the baseband filter for wide-band code division multiple
access (WCDMA) direct conversion integrated wireless receivers. This topology is
shown in Fig.
12.24
and is characterized by the following transfer function:
1
C
L
C
2
R
1
R
2
V
0
V
i
¼
ð
12
:
94
Þ
1
1
C
2
R
2
1
C
1
C
2
R
1
R
2
s
2
þ
s
C
1
R
2
þ
þ
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