Digital Signal Processing Reference
In-Depth Information
Fig. 3.18
Chip photographs of
a
the presented single-stage differential amplifier and
b
the presented
3-stage op amp built up with the single-stage amplifier. These circuits are made in technology
provided by Polymer Vision
Table 3.1
Summary of the
measurement results for the
single-stage differential
amplifier integrated on plastic
foil (Marien et al.
2010
,
2011
).
Specification
Value
Power supply
15V
Gain
15dB
Band width
0.6kHz
GBW
10kHz
CMRR
12dB
VTSR
>
12dB
Current consumption
1.5
µ
A
Power
15
µ
A
2mm
2
Chip area
2
×
single-stage amplifiers presented in Sect.
3.3.1
. In Sect.
3.3.2.1
the implementation of
the op amp is presented. Finally the measurement results of the op amp are presented
in Sect.
3.3.2.2
.
3.3.2.1 Implementation
The implementation of the 3-stage op amp is presented in Fig.
3.19
. It is built up
with three single-stage amplifiers. The first one is identical to the amplifier discussed
in Sect.
3.3.1
, whereas the second and the third amplifier are enlarged with a factor
3 and 9 respectively. As the operating points of the input and the output nodes in
the single-stage amplifier are different, a level shifter is required in between each
two consecutive amplifiers. In this design a passive implementation for this level
shifter, a high-pass filter, is applied. The passive implementation is preferred over a
level shifter based on a source follower, since the maximal simulated AC throughput
in a level shifter built with p-type organic transistors amounts to
60% whereas
the losses in the passive implementation are negligible and the optimal
∼
100%
throughput is reached. The passive implementation is identical to the high-pass filter
∼
