Hardware Reference
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a
b
CCII+
R
2
y
V
in
z
V
0
R
1
CCII+
x
x
V
in
z
V
0
R
2
y
R
1
Fig. 5.2 CCII-based amplifiers (a) Inverting (b) Non-inverting
For the inverting amplifier:
R
2
2
R
1
R
2
2
R
1
for 2R
p
>>
R
2
ð
5
:
5
Þ
R
2
2
R
p
1
þ
For the non-inverting amplifier:
R
2
2
R
1
1
þ
R
2
2
R
1
þ
1
þ
ð
5
:
6
Þ
R
2
2
R
p
1
þ
whereas both the circuits have the same
3 dB frequency given by
1
C
p
2
R
2
þ
1
R
p
2
C
p
R
2
ω
3
dB
¼
ð
5
:
7
Þ
It is, therefore, interesting that in both the cases, the 3-dB bandwidth can be set by
the feedback resistor R
2
after which the variable gain can be obtained by varying the
resistance R
1
. Thus, there is no gain-bandwidth conflict in case of the inverting and
non-inverting amplifiers made from the CCIIs.
It has been experimentally verified that setting R
2
at 4.7
ʩ
and varying R
1
produced voltage gain varying from unity to over 100 with
3 dB bandwidth of
2.7 MHz at all values of the gains when the current conveyor was realized by BiFET
op-amp LF351 and CA3096AE transistor arrays using the operational mirrored
amplifier based formulation. It was also noticed that because in the inverting
configuration the Y-terminal has been grounded this forces the output terminal of
the internal op-amp to be virtually grounded thereby suppressing the slewing
mechanism of the internal op-amp due to which maximum slew rate recorded for
the inverting amplifier has been found to be as high as 100 V/us!
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