CMOS AMPLIFIER MODULE ALLOWING FOR VOLTAGE, CURRENT,
TRANSIMPEDANCE AND TRANSADMITTANCE TRANSFER FUNCTIONS
IMPLEMENTATIONS
Md. A.H. Talukder and R. Raut
Department of Electrical and Computer Engineering
Concordia University
1455 DE Maisonneuve Blvd. West, Montreal, Canada, H3G 1M8
e-mail: m_talukd@encs.concordia.ca, rabinr@ece.concordia.ca
Abstract— This article presents a universal amplifier module
(UAM), implemented in 180 nm CMOS technology, that can be
configured to function as a (i) voltage controlled voltage source
(VCVS), (ii) current controlled current source (CCCS), (iii)
voltage controlled current source (VCCS), (iv) current
controlled voltage source (CCVS), and (v) current conveyor
(type II). As a result, the amplifier can be used to produce four
kinds of basic circuit transfer functions, i.e., voltage-, current-,
transadmittance- and transimpedance- transfer functions. This
is validated by presenting simulation results for a second order
voltage, current, transadmittance and transimpedance bandpass filter (BPF) transfer functions using only three UAM
devices. The device is expected to be useful in a complex VLSI
system environment where interfacing between sub-systems
with varied impedance levels is required.
Keywords— Universal amplifier module (UAM), CMOS analog
integrated circuits, Voltage and current mode signal processing,
Transadmittance filter (TAF), Transimpedance filter (TIF).
I.
INTRODUCTION
The Advent of CMOS technology has facilitated the
invention of several analog amplifiers, such as operational
amplifiers, operational transconductance amplifiers etc. [12]. These amplifiers have been used for both voltage and
current mode signal processing. In the recent past people
have introduced new circuit modules that can produce
voltage and current mode transfer functions only [3-4]. In
this article we report a UAM that can be configured as any
one of the four basic electronic amplifiers (i.e., VCVS,
VCCS, CCVS, CCCS) as well as a type II Current Conveyor
(CCII). The UAM introduced by us can produce
transadmittance-, and transimpedance- transfer functions, in
addition to voltage and current-mode transfer functions.
Thus it can be used to produce four kinds of transfer
functions. In section II, the design principles of the proposed
UAM with different sub-systems are discussed and
principles of implementing the four basic amplifiers as well
as a CCII with the UAM are described. In section III, several
performance parameters measured by HSPICE simulation on
the post layout extracted data file are presented. Section IV
presents the configurations for realizing second-order band-
pass filters as voltage-, transadmittance, curren- and
transimpedance transfer functions using only three UAM
devices. The response curves for all the four filter transfer
functions are presented. Section V concludes the article.
II.
THE AMPLIFIER MODULE
A. The circuit
Figure 1 shows the schematic diagram of one-half of the
fully differential UAM. The transistors M0-M3 provide the
bias currents. We will discuss the system by considering the
half-system comprised of transistors M17, MX4-MX23.
Transistors M17, MX8, MX10 serve as current mirror bias
sources. Corresponding transistors in the other half-system
are labelled as MY4, MY5 ... and so on. The transistors
MX4-MX7 depict the half-system of the differential voltageand current- input terminals of the fully differential system.
Following the input stage, there are voltage level shifter
stages with frequency compensation circuit (MX8-MX13),
and a voltage output buffer circuit (MX14-MX16). A wideband transconductor (MX20-MX23) [5] serves as the output
current buffer circuit. The pass transistor MX18 activated by
the digital control signal D1 (1/0) facilitates the gate-drain
connected transistors (MX6-MX7) to receive an input
current signal for current-mode operations. Similarly, the
pass transistor MX19 activated by the digital control signal
D2 (0/1) can deliver the output either from the lowimpedance voltage buffer (for voltage or transimpedance
amplifier operation), or from the high-impedance current
buffer (for current or transadmittance amplifier operation).
The digital control signals D1, D2 thus can configure the
UAM for four-mode signal processing applications, i.e., (i)
voltage, (ii) trans-admittance, (iii) current, and (iv) transimpedance transfer functions.
B. Implementations of four basic amplifiers and a CCII
The principles of configuring the UAM as four basic
electronic amplifiers and a CCII are presented in table I. The
2012 25th IEEE Canadian Conference on Electrical and Computer Engineering (CCECE)
978-1-4673-1433-6/12/$31.00 ©2012 IEEE
Figure 1: Schematic diagram of half circuit of the universal amplifier module (UAM)
phases (ON or OFF) of the switches D1, D2 that are used to
choose voltage or current signal to be applied at the input or
sample the signals from the output buffer are also shown in
the table.
C. Layout data
The UAM of Fig.1 has been laid out in 180 nm CMOS
technology. The layout is connected with the pad frame and
is ready for fabrication. Figure 2 shows the layout view of
the UAM. Chip area of the UAM is 0.7 mm2 and it consumes
7.179 mW of power from ±1.3 V supply. Table II presents
the dimensions of the transistors (M0-MX23) used in halfcircuit of the UAM.
III.
RESULTS
A. Design validation
Post layout simulations of the different sub-systems of
the UAM using HSPICE provide similar results as the values
predicted by appropriate theoretical formulae. The DA stage
layout block provides gain of 55.34 whereas the theoretical
gain is 56. The level shifter stages layout block provide gain
of 126.5 and 133.93 respectively whereas theoretical values
are 125.11 and 149 respectively. The voltage buffer stage
provides gain of 0.84 whereas the theoretical gain is 0.73.
B. Performance parameters
Table III presents several important performance
parameters of the UAM obtained by HSPICE simulations
together with similar results reported by other researchers. In
some cases, comparative work of other researchers can not
cited since a device like the UAM has not been introduced in
the past.
IV.
APPLICATION EXAMPLES
A. Voltage mode filter (VTF) and transadmittance filter
(TAF) implementation
The proposed amplifier module can be used to implement
identical (except for a multiplicative constant) voltage
(VTF)- and transadmittance (TAF) mode 2nd order BPFs.
Figure 3 presents the configuration for the band pass filters
(VTF and TAF) using Ackerberg, Mossberg’s structure [6].
For the elements in Fig. 3, the transfer function is given by:
1
s
I
Vo1
RC1
(4.1)
=−
= o
r
1
Vi
Vi
2
1
s +s
+
R1C1 C1C 2 R2 rr2
From equation (4.1), it is seen that, the VTF (=Vo1/Vi) and
the TAF (=Io/Vi) have the same form. The simulated
frequency responses are shown in Fig. 4. Each of the filters
has center frequency of fp = 10 KHz and pole-Q factor = 2.5.
BPF response of VTF, TAF, CTF, TIF
80
VTF (dB)
TAF (dBmho)
CTF (dB)
TIF (dBohm)
60
40
20
dB
0
-20
-40
-60
-80
-100
-120
1.E+00
1.E+01
1.E+02
1.E+03
frequency
1.E+04
1.E+05
1.E+06
Figure 4: Frequency response of band-pass VTF, TAF, CTF
and TIF using three UAMs.
Figure 2: Layout view of the universal amplifier module
Configuration for the CTF and TIF are not shown here for
lack of space. Frequency response of the CTF and TIF are
included in Fig. 4. All the filters have same center frequency
(10 KHz) and pole-Q factor (2.5).
V.
Figure 3: Implementation of band-pass VTF and TAF using
the UAM
B. Current mode filter (CTF) and transimpedance filter
(TIF) implementation
The proposed UAM can also be used to implement
identical current-mode (CTF) and transimpedance (TIF)
function filters. The transfer function is given by:
Io
=−
I i1
s
1
RC1
r1
1
s2 + s
+
R1C1 C1C 2 R 2 rr2
=
Vo
I i1
(4.2)
From equation (4.2), it is seen that, the CTF (=Io/Ii1) and the
TIF (=Vo/Ii1) have the same form. The CTF is obtained
directly from the VTF of Fig. 3 by just reversing the inputoutput ports of the each UAM device in the VTF and
applying current signal at the transposed input port. This
involves application of the principle of transposition [6].
CONCLUSIONS
A universal amplifier module (UAM) in 180 nm CMOS
technology has been proposed in this article. The UAM is
configurable for either voltage or current mode signal
processing by digitally controlled switches and can provide
four types of transfer functions, i.e., voltage-, current-,
transadmittance- and transimpedance- transfer functions.
Several performance parameters of the proposed amplifier
module obtained by HSPICE simulations on the post layout
extracted data have been reported. Simulated responses of a
second order voltage-mode (VTF), current-mode (CTF),
transadmittance (TAF) and transimpedance (TIF) band-pass
filter transfer functions using only three UAM devices are
reported. The UAM will be a desirable active device for
multi-mode signal processing in a complex system where
interfacing between adjacent sub-systems with any one of
four kinds of possible input/output impedance levels need be
established optimally.
ACKNOWLEDGEMENTS
The work was supported by a research grant from the
Natural Science and Engineering Research Council
(NSERC), Canada, and a grant in support for research thesis
(SRT) from the Faculty of Engineering and Computer
Science, Concordia University, Montreal, Canada.
REFERENCES
[1] K. Khare, N. Khare and P.K. Sethiya, ‘Analysis of low voltage rail-torail CMOS operational amplifier design,’ International Conference on
Electronic Design, 2008, December 1-3, Penang, Malaysia, pp. 1-4.
[2] E. Sanchez-Sinencio and J. Silva-Martinez, ‘CMOS transconductance
amplifiers, architectures and active filters: a tutorial,’ IEE Proceedings G –
Circuits, Devices and Systems, 2000, February, vol. 147, issue 1, pp. 3-12.
TABLE II: TABLE FOR DIMENSIONS OF THE TRANSISTORS IN THE HALF-
[3] P. Lung Chu, and H. Pin Chen, ‘Versatile voltage-mode multifunction
biquadratic filter employing DDCCs’, International Conference on SolidState and Integrated-Circuit Technology, 2008, October, pp. 1789-1793.
[4] P. Mongkolwai, T. Pukkalanun, and W. Tangsrirat, ‘Current-mode
universal biquad with orthogonal ωp-Q tuning using OTAs’, International
Conference on Information, Communications & Signal processing, 2007,
December, pp. 1-4.
[5] R. Raut, ‘Wideband CMOS Transconductor for Analog VLSI Systems’,
IEEE Transactions on Circuits and Systems II: Analog and Digital Signal
Processing, 1996, November, vol. 43, issue 11, pp. 775–776.
[6] R. Raut, M. N. S. Swamy, and Nong Tian, ‘Current-Mode Filters Using
Voltage Amplifiers’, Circuits Systems and Signal Processing, 2007,
September/October, vol. 26, issue 5, pp. 773-792.
[7] K. J. de Langen, and J. H. Huijsing, ‘Compact low-voltage powerefficient operational amplifier cells for VLSI’, IEEE Journal of Solid-State
Circuits, 1998, October, vol. 33, issue 10, pp. 1482-1496.
[8] M. Abdulai and P. Kinget, ‘A 0.5 V Fully Differential Gate-input
Operational Transconductance Amplifier with Intrinsic Common-Mode
Rejection’, IEEE ISCAS 2006, May 21-24, Island of Kos, Greece, pp. 28372840.
CIRCUIT OF THE PROPOSED AMPLIFIER MODULE
TRANSISTORS
W (µm)
L (µm)
M0, M1, MX15
20
1.2
M2, M3
10
1.2
MX4
40
1.2
MX5
23.4
1.2
MX6
74.2
1.2
MX7, MX12
13
1.2
M17
95
1.2
MX8
70
1.2
MX9
11.9
1.2
MX10
37
1.2
MX13
1
2.3
10.1
1
TABLE I: CONFIGURING THE UAM FOR FIVE DIFFERENT BUILDING BLOCKS
Switching position
Types of amplifier
MX11
D1 = OFF, D2 = ON
D1 = OFF, D2 = OFF
D1 = ON, D2 = OFF
D1 = ON, D2 = ON
D1 = OFF, D2 = OFF
VCVS
VCCS
CCCS
CCVS
CCII
MX14
9
1.2
MX16
7.7
1.2
MX20
65
1.5
MX21
70
1.5
MX22, MX23
1.5
1.5
TABLE III: TABLE FOR PERFORMANCE PARAMETERS MEASUREMENT OF THE UAM TOGETHER WITH SIMILAR RESULTS REPORTED BY OTHERS
Voltage Amplifier (VCVS)
Transadmittance Amplifier
(VCCS)
This work
Other [7]
This work
CMOS Technology
180 nm
160 nm
Power supply
±1.3 V
Parameters
Other [8]
Transimpedance
Amplifier
(CCVS)
Current
Amplifier
(CCCS)
180 nm
180 nm
180 nm
180 nm
1.8V – 7V
±1.3 V
0.5 V
±1.3 V
±1.3 V
Open loop Gain
117.8 dB
86 dB
7.22 dB A/V
55 dB
165.1 dBΩ
54.32 dB
Unity gain BW
272.7 MHz
4 MHz
72.83 KHz
8.72 MHz
1.28 GHz
8.92 MHz
Phase margin
56.90
670
64.40
610
53.50
44.120
Gain margin
49.86 dB
-
68.83dB
-
88.09 dB
58.76 dB
Input offset
-97.33 pV
6 mV
-11.14 pV
-
1.49 µA
-
Input CMR
-690 mV ↔
+467.7 mV
Vss –0.5V↔
Vdd – 1.3V
-1.069 V ↔
+1.069 V
-
-0.4 mA ↔
+10 mA
-10 mA ↔
+53.37 µA
Output swing
-117.9 mV ↔
328.5 mV
Vss + 0.1 V
↔Vdd–0.1V
-1.025 µA ↔
-689.1 µA
-
-252 mV ↔
+1.048 V
-1.054 mA ↔
+947.2 mA
Slew rate
2.42 V/µs
4 V/µs
0.45 V/µs
1.35 V/µs
3.2 V/µs
0.22 V/µs
CMRR
200.79 dB
-
156.01 dB
61.9 dB
78.3 dB
83.17 dB
PSRR
82.74 dB
-
48.21 dB
-
84.55 dB
87.93 dB
Output offset
8.8 nV
-
90 fA
-
-260.5 µV
-
Output resistance
1.1 KΩ
-
115.62 KΩ
200 KΩ
1.1 KΩ
115.62 KΩ
Input resistance
∞
-
∞
-
0.2 KΩ
0.2 KΩ
Power dissipation
7.179 mW
9 mW
7.179 mW
77 µW
7.179 mW
7.179 mW