This paper presents an electronically tunable current-mode SIMO/MISO universal biquad filter using multioutput current controlled current conveyor transconductance amplifiers (MO-CCCCTAs). The proposed filter employs only two CCCCTAs and two grounded capacitors. The proposed configuration can be used as either single input multi-output (SIMO) or multi (three) input single output (MISO) current mode filter. It can realize all five different standard filter functions i.e. low-pass (LP), band-pass (BP), high-pass (HP), band-reject (BR) and all-pass (AP). The circuit enjoys an independent current control of pole frequency and bandwidth. Both the active and passive sensitivities are no more than unity. The validity of proposed filter is verified through computer simulations using PSPICE, the industry standard tool.

1. ACEEE Int. J. on Electrical and Power Engineering, Vol. 01, No. 03, Dec 2010
Electronically Tunable Current-Mode
SIMO/MISO Universal Biquad Filter Using MO-
CCCCTAs
S. V. Singh1, S. Maheshwari2, and D. S. Chauhan3
1
Department of Electronics and Communications, Jaypee University of Information Technology,
Waknaghat, Solan-173215 (India)
Email: sajaivir@rediffmail.com
2
Department of Electronics Engineering, Z. H. College of Engineering and Technology,
Aligarh Muslim University, Aligarh-202002 (India)
Email:sudhanshu_maheshwari@rediffmail.com
3
Department of Electrical Engineering, Institute of Technology, Banaras Hindu University,
Varanasi-221005 (India)
Email:pdschauhan@gmail.com
Abstract— This paper presents an electronically tunable matching conditions. Unfortunately these reported circuits [2-
current-mode SIMO/MISO universal biquad filter using multi- 23] suffer from one or more of the following drawbacks:
output current controlled current conveyor transconductance (i). Lack of electronic tunability [2-3, 15-17, 22].
amplifiers (MO-CCCCTAs). The proposed filter employs only (ii). Excessive use of active and/or passive elements [2-
two CCCCTAs and two grounded capacitors. The proposed 5, 7-18, 21-23].
configuration can be used as either single input multi-output (iii). Can not provide completely standard filter functions
(SIMO) or multi (three) input single output (MISO) current [4-6, 10].
mode filter. It can realize all five different standard filter (iv). Can not provide explicit current outputs [4-6].
functions i.e. low-pass (LP), band-pass (BP), high-pass (HP), (v). Use of floating passive elements [6-7, 19].
band-reject (BR) and all-pass (AP). The circuit enjoys an (vi). Require minus input current signal and/or double
independent current control of pole frequency and bandwidth. input current signal to realize AP filter function [19-
Both the active and passive sensitivities are no more than 21].
unity. The validity of proposed filter is verified through In spice of fact that most of these current-mode filters
computer simulations using PSPICE, the industry standard are either SIMO or MISO. However, the circuit reported in
tool. refs. [22-23] can be used as SIMO as well as MISO current-
mode filter from the same configuration but these circuits
IndexTerms—CCCCTA, current-mode, universal, biquad, [22-23] uses excessive number of active and passive
filter components. CCCCTA is relatively new active element [24]
and has received considerable attentions as current mode
I. INTRODUCTION active element, because its trans-conductance and parasitic
The current-mode active filter, where information is resistance can be adjusted electronically, hence it does not
represented by the branch currents of the circuits rather than need a resistor in practical applications. This device can be
the nodal voltages as of voltage-mode active filter, posses operated in both current and voltage modes, providing
many unique and attractive characteristics over their voltage- flexibility. In addition, it can offer several advantages such as
mode counter parts including small nodal time constant, high high slew rate, high speed, wider bandwidth and simpler
current swing in the presence of a low supply voltage, implementation. All these advantages together, its current-
reduced distortion and better ESD immunity [1 ]. During the mode operation makes the CCCCTA, a promising choice for
last one decade and recent past a number of current-mode realizing active filters [24]. In this paper an electronically
active filters have been reported in the literature [2-23], using tunable current-mode SIMO/MISO universal biquad filter
different current conveyors (CCs). These current-mode active employing two MO-CCCCTAs and two grounded capacitors.
filters are broadly classified as SIMO [2-14, 22-23] or MISO The proposed configuration can be used as either SIMO or
[15-21, 22-23] current-mode filters. The SIMO current-mode MISO current mode filter, without change in circuit
filters can realize second order LP, BP, HP, BR and AP configuration. It can realize all five different standard filter
responses simultaneously, without changing the connection functions i.e. LP, BP, HP, BR and AP. The circuit enjoys an
of the input current signal and without imposing any independent current control of pole frequency and
restrictive conditions on the input signal. The MISO current- bandwidth. The circuit possesses low active and passive
mode filters can realize all the standard filter function sensitivity performance. The performances of proposed
through appropriate selection of the signals without any circuit are illustrated by PSPICE simulations.
36
© 2010 ACEEE
DOI: 01.IJEPE.01.03.100

2. ACEEE Int. J. on Electrical and Power Engineering, Vol. 01, No. 03, Dec 2010
I OUT 1 = −
( I in1 + I in 2 ) C2 s + I in3 g m 2 (5)
D(s)
g m 2 [ I in 3C1 RX 2 s + ( I in 3 − I in1 − I n 2 ) ]
I OUT 2 = (6)
D( s)
I in1 ( D ( s ) − C2 s ) − I in 2C2 s − I in 3 g m 2
I OUT 3 = (7)
D(s)
g m1 RX 2 ⎡( I in1 + I in 2 ) C2 s + I in 3 g m 2 ⎤
⎣ ⎦
I OUT 4 = (8)
D(s)
Figure 1. CCCCTA Symbol
Where D ( s ) = s 2C1C2 RX 2 + sC2 + g m 2 (9)
II. CIRCUIT DESCRIPTION
The CCCCTA properties can be described by the It can be seen from (7) that proposed filter circuit can be
following equations used as three input single output (TISO) current-mode filter
and realizes five standard filter functions at current output
VXi = VYi + I Xi R Xi , I Zi = I Xi , I − Zi = − I Xi , IO = g mi VZi IOUT3 which are follow as:
(1) (i). An inverted BP with Iin2 = Iin and Iin3 = Iin1=0.
where Rxi and gmi are the parasitic resistance
at x terminal and transconductance of the ith CCCCTA (ii). A non-inverted HP with Iin2 = 0 and Iin3 = Iin1=
respectively. Rxi and gmi depend upon the biasing currents Iin.
IBi and ISi of the ith CCCCTA respectively. The schematic
symbol of CCCCTA is illustrated in Fig.1. The (iii). A non-inverted LP with Iin2 = Iin1= 0 and Iin3 =
implementation of MO-CCCCTA with CMOS transistors Iin.
[25] is shown in Fig.2. For CMOS model of CCCCTA
shown in Fig.2, Rx and gm can be expressed as (iv). A non-inverted BR with Iin1 = Iin and Iin3 = Iin2
= 0.
1 (v). A non-inverted AP with Iin1 =Iin2 = Iin and Iin3
RX = (2)
8β n I B = 0.
and In this design we can note that there are no need of any
component matching conditions, inverting-type input
gm = βn I S (3) current signal(s) and double input current signal(s) to
realize the above standard filter functions. Moreover,
W above proposed filter circuit can also be used as single
Where β n = μn COX (4)
input multi-output current-mode filter if Iin2 = Iin3 =0 and by
L
taking Iin1as single input current terminal. From (5) to (8)
where μn, COX and W/L are the electron mobility, gate the following current transfer functions can be obtained.
oxide capacitance per unit area and transistor aspect ratio,
respectively. I OUT 1 −C2 s
= (10)
I in1 D(s)
III. PROPOSED FILTER CIRCUIT
I OUT 2 − g m 2
The proposed electronically tunable current-mode = (11)
SIMO/MISO universal biquad filter circuit is shown in I in1 D( s)
Fig.3. It is based on two MO-CCCCTAs and two grounded
capacitors. Routine analysis of the proposed circuit yields I OUT 3 C1C2 RX 2 s 2 + g m 2
the following current transfer functions. = (12)
I in1 D(s)
37
© 2010 ACEEE
DOI: 01.IJEPE.01.03.100

3. ACEEE Int. J. on Electrical and Power Engineering, Vol. 01, No. 03, Dec 2010
Figure 2. Implementation of MO-CCCCTA using CMOS transistors
Substituting intrinsic resistances as depicted in (2) - (3), it
yields
1 1 1
⎛ 1 ⎞2 1 ⎛ C ⎞2 ⎛ I ⎞4
ωo = ⎜ βn ⎟ ( 8I B2 IS2 ) 4 , Q = ⎜ 1 ⎟ ⎜ S2 ⎟ (15)
⎝ C1C2 ⎠ ⎝ C2 ⎠ ⎝ 8I B2 ⎠
From (15), by maintaining the ratio IB2 and IS2 to be
constant, it can be remarked that the pole frequency can be
electronically adjusted by IB2 and IS2 without affecting the
quality factor. In addition, bandwidth (BW) of the system
can be expressed by
ωO 1 1
BW = = ( 8β n I B 2 ) 2 (16)
Q C1
Equation (15) shows that the bandwidth can be controlled
by IB2. From (15) and (16) , it is clear that parameter ωo
can be controlled electronically by adjusting bias current
IS2 with out disturbing parameter ωo/Q .
IV. NON-IDEAL ANALYSIS
Figure 3. Electronically tunable current-mode SIMO/MISO universal
biquad filter
Taking the non-idealities of CCCCTA into
account, the relationship of the terminal voltages and
I OUT 4 g m1 RX 2C2 s currents can be rewritten as follow.
= (13)
I in1 D( s)
VXi = βi VYi + I Xi R Xi , I Zi = α pi I Xi , I − Zi = −α ni I Xi ,
It can be seen from (10) to (13) that inverting BP,
an inverting LP, non-inverting BR and non-inverting BP IO = γ i g mi VZi (17)
filter responses are obtained from output currents IOUT1,
IOUT2, IOUT3 and IOUT4 respectively. HP and AP filter Where βi =1-εvi and εvi ( | εvi | <<1) represents the voltage
responses can be easily obtained from the currents IHP= tracking error from Y to X terminal, and αpi =1-εpi and εpi ( |
IOUT2 + IOUT3 and IAP= IOUT1 + IOUT3 respectively. εpi | <<1) represents the current tracking error from X to
Obviously, it is a single-input six-outputs current mode +Z terminal and αni =1-εni and εni ( | εni | <<1) represents the
universal biquad filter. The pole frequency (ωo), the quality current tracking error from X to -Z terminal and γi is the
factor (Q) and Bandwidth (BW) ωo /Q of each filter can be trans-conductance inaccuracy factor from Z to X terminal.
expressed as The non-ideal analysis of the proposed filter in Fig.3 yields
1 1
the denominator of the transfer functions as
⎛ g m2 ⎞ 2 ⎛ C R g ⎞2 ωO 1
ωo = ⎜ ⎟ , Q = ⎜ 1 X2 m2 ⎟ , BW = =
⎝ C1C 2 R X 2 ⎠ ⎝ C2 ⎠ Q C1R X2 D( s ) = s 2α n1C1C2 RX 2 + sα p1α n 2 β 2C2 + α n1α n 2 β 2γ 2 g m 2
(14) (18)
38
© 2010 ACEEE
DOI: 01.IJEPE.01.03.100

4. ACEEE Int. J. on Electrical and Power Engineering, Vol. 01, No. 03, Dec 2010
In this case, the ωo and Q are changed to
1 1
⎛ α β γ g ⎞2 α ⎛ γ C g R ⎞2
ωo = ⎜ n 2 2 2 m2 ⎟ , Q = n1 ⎜ 2 1 m2 X2 ⎟ (19)
⎝ C1C2 R X2 ⎠ α p1 ⎝ α n 2β2 C2 ⎠
The active and passive sensitivities of the proposed circuit
as shown in Fig.3, can be found as
ω 1 ωo 1
SC1o,C2 , RX 2 = − , Sγ 2 ,α n 2 , β 2 , g m 2 = , (a)
2 2
ω
Sα no1 ,α p1 ,γ1 , β1 , gm1 = 0 (20)
1 Q 1 Q
SC2 ,α n 2 , β2 = − , S RX 2 ,C1 ,γ 2 , gm 2 = , Sα p1 = −1 ,
Q
2 2
Sα n1 = 1 , S RX 1 ,γ1 , β1 = 0
Q Q
(21)
From the above results, it can be observed that all the (b)
sensitivities are low and no longer than one in magnitude.
V. SIMULATION RESULTS
P-spice simulations are carried out to demonstrate the
feasibility of the proposed circuit using CMOS
implementation as shown in Fig.2. The simulations use a
0.35µm MOSFET from TSMC (the model parameters are
given in Table1). The dimensions of PMOS are determined
as W=3µm and L=2µm. In NMOS transistors, the
dimensions are W=3µm and L=4µm. Fig.4 Shows the
simulated current gain responses of the LP, BP, BR, HP (c)
and AP of SIMO configuration of the proposed circuit in
Fig.3. Fig.5 shows the simulated current gain and phase
responses of the LP, BP, BR, HP and AP of MISO
configuration of the proposed circuit in Fig.3. The
proposed filter is designed with IB1=IB2=6µA, IS1=
IS2=54.5µA and C1=C2=35pf. The supply voltages are
VDD=-VSS=1.85V. The simulated pole frequency is
obtained as 333 KHz. The simulation results agree quite
well with the theoretical analysis.
(d)
(e)
Figure 5 Current gain and phase responses of the (a) BP, (b) HP, (c)
LP, (d) BR and (e) AP of MISO configuration of the proposed
Figure 4. Current gain responses of the LP, BP, BR, HP and AP of SIMO circuit in Fig.3.
configuration of the proposed circuit in Fig.3
39
© 2010 ACEEE
DOI: 01.IJEPE.01.03.100

5. ACEEE Int. J. on Electrical and Power Engineering, Vol. 01, No. 03, Dec 2010
Further simulations are carried out to verify the total VI. CONCLUSION
harmonic distortion (THD). The circuit is verified by
applying a sinusoidal current of varying frequency and An electronically tunable current-mode SIMO/MISO
amplitude 20µA.The THD are measured at the LP output universal bquad filter using only two MO-CCCCTAs and two
(IOUT2). The THD is found to be less than 5% while grounded capacitors is proposed. The proposed filter offers
frequency is varied from 10 KHz to 150 KHz. The time the following advantages
domain response of LP output (IOUT2) is shown in Fig.6. It (i). Simultaneously realizes LP, BP, HP, BR and AP
is observed that 40µA peak to peak input current sinusoidal responses with the single input three output or three
signal levels are possible with out significant distortions. input single output from same configuration.
(ii). Both the capacitors are grounded and ideal for
integrated circuit implementation.
(iii). Low sensitivity figures.
(iv). Filter parameters- ωo , Q and ωo / Q are
electronically tunable with bias current(s) of
CCCCTA(s)
(v). ωo and ωo / Q are orthogonally tunable.
(vi). No need to use inverting-type input current signals
or double input current signals to realize all five
standard filter functions.
(vii). Availability of explicit current outputs (i.e. high
impedance output nodes) without requiring any
additional active elements.
Figure 6. Time domain input and LP output (IOUT2) waveforms of the With above mentioned features it is very suitable to realize
proposed circuit in Fig .3. the proposed circuit in monolithic chip to use in battery
powered, portable electronic equipments such as wireless
Table 1. 0.35μm level 3 MOSFET parameters communication system devices.
NMOS:
LEVEL=3 TOX=7.9E-9 NSUB=1E17 GAMMA=0.5827871
PHI=0.7 VTO=0.5445549 DELTA=0 UO=436.256147 ETA=0
THETA=0.1749684 KP=2.055786E-4 VMAX=8.309444E4
KAPPA=0.2574081 RSH=0.0559398 NFS=1E12 TPG=1 XJ=3E-7
LD=3.162278E-11 WD=7.04672E-8 CGDO=2.82E-10
CGSO=2.82E-10 CGBO=1E-10 CJ=1E-3 PB=0.9758533
MJ=0.3448504 CJSW=3.777852E-10 MJSW=0.3508721
PMOS:
LEVEL =3 TOX = 7.9E-9 NSUB=1E17 GAMMA=0.4083894
PHI=0.7 VTO=-0.7140674 DELTA=0 UO=212.2319801
ETA=9.999762E-4 THETA=0.2020774 KP=6.733755E-5
VMAX=1.181551E5 KAPPA=1.5 RSH=30.0712458 NFS=1E12
TPG=-1 XJ=2E-7 LD=5.000001E-13 WD=1.249872E-7
CGDO=3.09E-10 CGSO=3.09E-10 CGBO=1E-10 CJ=1.419508E-3
PB=0.8152753 MJ=0.5 CJSW=4.813504E-10 MJSW=0.5
40
© 2010 ACEEE
DOI: 01.IJEPE.01.03.100

6. ACEEE Int. J. on Electrical and Power Engineering, Vol. 01, No. 03, Dec 2010
REFERENCES [14].N. Pandey, S. K. Paul and S. B. Jain, “A new electronically
tunable current-mode universal filter using MO-CCCII,”
[1].G. W. Roberts and A. S. Sedra, “All current-mode frequency Analog Integrated Circuits and Signal Processing, vol. 58,
selective circuits,” Electronics Lett., vol .25, pp. 759-761, pp. 171-178, 2009.
1989. [15].M. T. Abuelma'atti and N. A. Tassaduq, “A novel three
[2].S. Özoğuz, A. Toker, and O. Çiçekoğlu, ‘‘New current-mode inputs and one output universal current-mode filter using
universal filters using only four (CCII+)s,’’ Microelectronics plus-type CCIIs,” Microelectronics J., vol. 30, pp. 287-292,
J., vol. 30, pp. 255-258, 1999. 1999.
[3].C. Wang, Y. Zhao, Q. Zhang and S. Du, “A new current [16].E. O. Günes, A. Toker and S. Özoğuz, “Insensitive current-
mode SIMO-type universal biquad mploying multi-output mode universal filter with minimum components using dual-
current conveyors (MOCCIIs),”Radioengineering, vol.18, output current conveyors,” Electronics Lett., vol. 35, pp.
pp. 83-88, 2009. 524-525, 1999.
[4].W. Kiranon, J. Kesorn, and N. Kamprasert, “Electronically [17].R. Senani, “New universal current mode biquad employing
tunable multi-function translinear-C filter and oscillators,” all grounded passive components but only two DOCCs,” J.
Electronics Lett., vol. 33(7), pp. 573-574, 1997. of Active and Passive Devices, vol. 1, pp. 281-288, 2006.
[18].M. T. Abuelma'atti and M. L. Al-qahtani, “Universal current-
[5].I. A. Khan and M. H. Zaidi, “Multifunction translinear-C contolled current-mode filter with three inputs and one
current mode filter,” Int’l J. Electronics, vol. 87, pp. 1047- output using current controlled conveyor,” Active Passive
1051, 2000. Electronics Components, vol. 21, pp. 33-41, 1998.
[6].M. Sagbas and K. Fidaboylu, “Electronically tunable current- [19].C. M. Chang, “Universal active current filter using single
mode second order universal filter using minimum second-generation current controlled conveyor,” Int’l J.
elements,” Electronics Lett., vol. 40, pp. 2-4, 2004. Circuits, Systems and signal Processing, vol .1, pp. 194-198,
[7].E. Yuce, S. Minaei, and O. Cicekoglu, “Universal current- 2007.
mode active-C filter employing minimum number of passive [20].W. Tangsrirat and W. Surakampontorn, “Low-component
elements,” Analog Integrated Circuits and Signal current-mode universal filter using current controlled
Processing, vol. 46, pp. 169–171, 2006. conveyors and grounded capacitors,” J. of Active and Passive
[8].S. Maheshwari and I. A. Khan, “High performance versatile Devices, vol. 8, pp. 259-264, 2009.
translinear-C universal filter,” J. of Active and Passive [21].W. Tangsrirat and W. Surakampontor, “High output
Electronic Devices, vol. 1, pp. 41-51, 2005. impedance current-mode universal filter employing dual-
[9].R. Senani, V. K. Singh, A. K. Singh, and D. R. Bhaskar, output current-controlled conveyors and grounded
“Novel electronically controllable current mode universal capacitors,” Int’l J. Electronics and communication (AEU),
biquad filter,” IEICE Electronics Express, vol. 1(14), pp. vol. 61, pp. 451-457, 2007.
410-415, 2004. [22].H. Y. Wang and C. T. Lee, “Versatile insensitive current-
[10]. S. Minaei and S. Türköz, “Current-mode electronically mode universal biquad implementation using current
tunable universal filter using only plus-type current conveyors,” IEEE Transactions on Circuits and Systems-II:
controlled conveyors and grounded capacitors,” ETRI Analog and Digital Signal Processing,” vol. 48, pp. 409-413,
Journal, vol. 26(4), pp .292-296, 2004. 2001.
[11].T. Tsukutani, Y. Sumi, S. Iwanari and Y. Fukui, “Novel [23].H. P. Chen and P. L. Chu, “Versatile universal electronically
current-mode biquad using MO-CCCIIS and grounded tunable current-mode filter using CCCIIs,” IEICE
capacitors,” Proceeding of 2005 International Symposium on Electronics Express, vol. 6(2), pp. 122-128, 2009.
Intelligent Signal Processing and Communication Systems, [24].M. Siripruchyanun and W. Jaikla, “Current controlled
pp. 433-436, 2005. current conveyor transconductance amplifier (CCCCTA): A
[12].C. Wang, H. Liu and Y. Zhao, “A new current-mode current building block for analog signal processing,” Electrical
controlled universal filter based on CCCII(±),” Circuits Engineering,” vol. 90, pp. 443-455, 2008.
System Signal Process, vol.27, pp. 673-682, 2008. [25]. M. Siripruchyanun, P. Silapan and W. Jaikla, “Realization
[13].S. Maheshwari and I. A. Khan, “ Novel cascadable current- of CMOS current controlled current conveyor
mode translinear-C universal filter,” Active Passive transconductance amplifier and its applications,” J. of Active
Electronics Components, vol. 27( 4), pp. 215-218, 2004. and Passive Electronic Devices, vol. 4, pp. 35-53, 2009.
41
© 2010 ACEEE
DOI: 01.IJEPE.01.03.100