Inter national J our nal of Electrical and Computer Engineering (IJECE) V ol. 6, No. 4, August 2016, pp. 1499 1505 ISSN: 2088-8708, DOI: 10.11591/ijece.v6i4.9797 1499       I ns t it u t e  o f  A d v a nce d  Eng ine e r i ng  a nd  S cie nce   w     w     w       i                       l       c       m     MOCCCDT A-based Curr ent Mode T unable Uni v ersal Biquad Filter f or Bluetooth A pplications Jy oti Sharma and Shantanu Chakraborty Department of ECE, BIT Mesra, Jaipur Campus, India Article Inf o Article history: Recei v ed Feb 5, 2016 Re vised May 22, 2016 Accepted Jun 8, 2016 K eyw ord: MOCCCDT A Current mode Biquad Filter T unability Bluetooth Standard ABSTRA CT In the last decade, there has been much ef fort to reduce the supply v oltage of electronic cir - cuits due to the demand for portable and battery-po wered equipment. Since a lo w-v oltage operating circuit becomes necessary , the current-mode technique is ideally suited for this purpose more than the v oltage-mode one. In this paper , perform ance of multi output cur - rent controlled current dif ferencing transconductance amplifier (MOCCCDT A) is e v aluated using 180nm, 90nm and 45nm CMOS technology . It is found that the 45nm CMOS-based MOCCCDT A pro vides highest frequenc y i.e. 33GHz. Further a Uni v ersal biquad filter has been designed using a single MOCCCDT A as an acti v e element and tw o capacitors. Fil- ter of fers high frequenc y in GHz. T unability of all the filter outputs with respect to a bias current has been analyzed. The tunability of the filter circuit for Bluetooth applications is also sho wn in this w ork. The performances of MOCCCDT A circuit and Uni v ersal biquad filter are illustrated by HSPICE. The simulation results are found to be in agreement with the theoretical predictions. Copyright c 2016 Institute of Advanced Engineering and Science . All rights r eserved. Corresponding A uthor: Jyoti Sharma Assistant Professor BIT Mesra, Jaipur Campus 9929655006 jyotisharma@bitmesra.ac.in 1. INTR ODUCTION W ith the adv ent of inte grated circuit technology , it has becom e possible to design lar ger electronic circuits on a single chip. Mix ed-signal ICs are chips that contain both digital and analog circuits on the same chip. All the abo v e mentioned circuits can be designed indi vidually/ on a single chip by using either v oltage mode or current mode techniques. Similarly , the general trend in CMOS technology is to mak e the de vices smaller and smaller to increase the density and speed of digital circuits. It is also common to reduce the thickness of the g ate oxide in order to increase the dri ving capability of the transistor [1]- [3]. In addition, the t hickness reduction implies that the supply v oltage must be decreased to a v oid e xcessi v e electric field in the de vices. Also the number of components is increasing on a single chip, b ut it can only dissipate a limited amount of po wer per unit area. Since the increasing density of components allo ws more electronic functions per unit area, the po wer per electronic function has to be lo wered in order to pre v ent o v erheating of the chip [4]- [6]. Earlier the operational amplifier (O A) has s erv ed as the basic v oltage mode b uilding block in analog circuit design [1]- [3]. V oltage-mode operational amplifier (O A) circuits ha v e li mited bandwidth at high closed-loop g ains due to the constant g ain-bandwidth product. The moderate sle w-rate of the operational amplifier limits the lar ge- signal, high frequenc y operation. Also in the applications where wide bandwidth is required, lo w po wer consumption and lo w v oltage operation are needed simultaneously . In that case, v oltage-mode operational amplifier becomes too comple x. Therefore, v oltage mode circuits based on operational amplifier (O A) are not suitable for use in high fre- quenc y applications. Thus their limited performance as mentioned abo v e, led the analog designer to search for other possibilities and other b uilding blocks [7]. V oltage-mode circuits are those in which signal information is represented by v oltage at the nodes of the circuit, where as in current-mode circui ts, signal information is represented by current o wing in the branches of the circuit. In current mode circuits (CMCs) the complete circuit response is determined by J ournal Homepage: http://iaesjournal.com/online/inde x.php/IJECE       I ns t it u t e  o f  A d v a nce d  Eng ine e r i ng  a nd  S cie nce   w     w     w       i                       l       c       m     Evaluation Warning : The document was created with Spire.PDF for Python.
1500 ISSN: 2088-8708 the currents and the input/ output signals are primarily represented in current form. CMCs ha v e simple architecture and their operations do not depend on the supply v oltages [6]- [7]. The current mode circuits als o of fer high linearity , wide bandwidth, lo wer po wer consumption, simpler circuitry and better high frequenc y performance [2, 8–11]. In this w ork, a CMOS-based Multi Output Current Controlled Current Dif ferencing T ransconductance Am- plifier (MOCCCDT A) has been presented. Performance e v aluation of MOCCCDT A has been carried out using HSPICE through T ransient and A C responses. Ne xt a uni v ersal bi quad filter has been designed using MOCCCDT A that is capable of generating lo w-pass, high-pass, band-pass and band-reject responses. Circuit uses only a single MOCCCDT A and tw o capacitor and no resistors. The proposed circuit of fers se v eral adv antages such as minimum number of acti v e and passi v e components required, appropriate for high frequenc y operation in GHz and resistor less implementation. The paper is arranged as follo ws. Section II presents brief description of MOCCCDT A. Section III discusses the uni v ersal biquad filter . The simulation results of all the filter responses are discussed in section IV . The tunability of filter responses with the v ariation of bias current is also presented in section IV . Section V sho ws the tuning of band pass filter for Bluetooth applications. Section VI concludes the paper . 2. BRIEF INTR ODUCTION T O MUL TI OUTPUT CURRENT CONTR OLLED CURRENT DIFFERENC- ING TRANSCONDUCT ANCE AMPLIFIER (MOCCCDT A) The MOCCCDT A consists of the current dif ferencing transconductance amplifier (CDT A) as the basic b uild- ing block. The CDT A tak es tw o inputs Ip and In as currents and produces the current Iz at the impedence terminal. The current I z is proportional to the dif ference between the input currents. An equi v alent v oltage V z is produced on the impedence terminal due to the finite resistance of the terminal and the v oltage drop across it. The v oltage Vz so generated is then trans-conducted ac ross to the output terminal and the output current thus produced is proportional to the v alue of transconductance across the circuit gi v en by g m . It has finite input resistances Rp and Rn at input termi- nals. These parasitic resistances are equal and can be controlled by biasing currents. The MOCCCDT A is represented by a set of characteristic equation sho wn in Eq.1. V p = V n = 0; I z = I p I n ; I x = g m V z (1) where p and n are input terminals, z and x are output terminals and g m is the transconductance g ain. The parasitic resistances R p ; R n and the transconductance g ain g m are gi v en by Eq. 2 and 3. R p = R n = V T 2 I B 1 (2) g m = I B 2 2 V T (3) where I B 1 and I B 2 are the bias currents of the MOCC CDT A and V T is the thermal v oltage . The basic b uilding block of the MOCCCDT A is sho wn in Fig. 1 where Ip and In are the tw o input currents and Iz is the transimpedence current produced. At x terminal, we see that the output current is either in in v erted mode or in non- in v erted mode which is proportional to the transconductance. Figure 1. Block Diagram of Multi-output Current Controlled Current Dif ferencing T ransconductance Amplifier Fig. 2 sho ws the internal CMOS based circuit of MOCCCDT A. Port p and n are the input ports and Z1, Z2 and Z3 are the positi v e and ne g ati v e output current ports. Port X is also the output current port. IB1 and IB2 are the bias currents. IJECE V ol. 6, No. 4, August 2016: 1499 1505 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 1501 Figure 2. Internal Circuit of Multi-output Current Controlled Current Dif ferencing T ransconductance Amplifier 3. UNIVERSAL BIQ U AD FIL TER The current mode uni v ersal biquad filter is designed using single MOCCCDT A as an acti v e element and tw o grounded capacitors, which is easy to f abricate. The block diagram of the filter is sho wn in Fig. 3. In this filter , the multi-output CCCDT A of Fi g. 2 is used where currents I z 2 and I z 3 are obtained in opposite dir ections from I z 1 . Capacitors are used for high pass and band pass applications. Figure 3. Block Diagram of Uni v ersal Biquad Filter The transfer functions of high-pass, lo w-pass and band-pass filters are gi v en in Eq. 4-6. I H P I in = s 2 s 2 + s C 1 R n + g m C 1 C 2 R n (4) I LP I in = g m C 1 C 2 R n s 2 + s C 1 R n + g m C 1 C 2 R n (5) I B P I in = s C 1 R n s 2 + s C 1 R n + g m C 1 C 2 R n (6) The band-reject transfer function may be achie v ed by IBR= Iin-IBP and is gi v en in Eq.7. I B R I in = s 2 + g m C 1 C 2 R n s 2 + s C 1 R n + g m C 1 C 2 R n (7) MOCCCDT A-based Curr ent Mode T unable Univer sal Biquad F ilter for ... (Jyoti Sharma) Evaluation Warning : The document was created with Spire.PDF for Python.
1502 ISSN: 2088-8708 The pole frequenc y ! 0 and quality f actor Q are gi v en in Eq. 8 and 9. ! 0 = r g m C 1 C 2 R n = s n p 8 I B 1 I B 2 C 1 C 2 (8) Q = r C 1 g m R n C 2 = s C 1 p I B 2 C 2 p 8 I B 1 (9) 4. RESUL TS AND DISCUSSIONS The MOCCCDT A circuit has been implemented in 180nm, 90nm and 45nm CMOS technology . In order to ascertain the correct operation of the CMOS- based MOCCCDT A, transient and A C analyses were carried out using HSPICE. T ransient analysis has been carried out with 100 MHz sinusoidal input, for which the current relationship equations i.e. I z = I p I n and I x = g m V z are successfully v erified for all the three technology nodes. A C analysis for the CMOS-based MOCCCDT A re v eals e xcellent conformity between the input currents ( I p andI n ) and the output current ( I x ) till about 1GHz, 5Ghz and 10 GHz for 180nm, 90nm and 45nm technology nodes respecti v ely . The simulation results of transient and A C analyses of MOCCCDT A are sho wn in Fig. 4. (a) T ransient Res ponse at 180nm T echnology (b) T ransient Respons e at 90nm T echnology (c) T ransient Response at 45nm T echnology (d) A C Response at 180nm, 90nm and 45nm T echnology Figure 4. Results of HSPICE simulations for Z + , Z and X outputs of the MOCCCDT A of Fig. 2: (a)T ransient Analysis at 180nm (b) T ransient Analysis at 90nm (c) T ransient Analysis at 45nm and (d) A C Analysis at 180nm, 90nm, 45nm T echnology The v alues of po wer supplies, bias currents and bandwidth obtained for dif ferent technologies are sho wn in T able 1. It is observ ed that MOCCCDT A circuit of fers highest bandwidth among three for lo wer v alues of po wer supplies and bias current, thus more ef ficient. T able 1. P arameter V alues for Dif ferent T echnologies T echnology 180nm 90nm 45nm Vdd 1.25V 0.9V 0.45V Vss 1.25V 0.9V 0.45V Bias Current ( I B 1 ) 50 A 50 A 40 A Bias Current ( I B 2 ) 80 A 60 A 40 A Band W idth (GHz) 6.6 15 33 IJECE V ol. 6, No. 4, August 2016: 1499 1505 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 1503 The uni v ersal biquad filter circuit of Fig. 3 is simulated using HSPICE in 45 nm technology . The high-pass, lo w-pass, band-pass and band-stop responses are sho wn i n Fig. 5(a). Ef fect of v ariation in the filt er characteristics with bias current I B 1 and I B 2 of the MOCCCDT A w as also e xplored using HSPICE simul ations. Fig. 5(b) depicts the change in v arious filter characteristics as the bias currents is v aried from 10A to 50A in steps of 10A for all the four filter functions. (a) Band-Reject, Lo w-P ass, Band-P ass and High-P ass F ilter Re- sponses (b) V ariation in Filter Responses with the V ariation in Bias Cur - rents Figure 5. Results of Responses of Filter in Fig. 3: (a)Filter Responses in 45 nm T echnology and (b)Responses of v arious filter functions with the v ariation of bias currents from 10 A to 50 A in steps of 10 A T able 2 sho ws the v alues of peak-frequenc y and bandwidth obtained from the uni v ersal biquad filter of Fig. 3. It is observ ed that the frequenc y obtained is in GHz. Thus the filter is suitable for high frequenc y applications. T able 2. Peak-frequenc y and 3dB bandwidth of Uni v ersal Biquad Filter Filter Lo w-P ass High-P ass Band-P ass Peak Frequenc y (GHz) 1.27 3.34 2.36 Bandwidth (GHz) 2.44 1.95 2.71 The present w ork [7, 12–15] has also been compared with the w ork done in the pre vious year on dif ferent technologies according to the acti v e element used, bias currents, passi v e elements used etc. THe comparison has been sho wn in table 6. Figure 6. Comparison of the present w ork with the pre vious w orks MOCCCDT A-based Curr ent Mode T unable Univer sal Biquad F ilter for ... (Jyoti Sharma) Evaluation Warning : The document was created with Spire.PDF for Python.
1504 ISSN: 2088-8708 4.1. TUNING OF B AND P ASS FIL TER FOR BLUET OO TH APPLICA TION Bluetooth is a wireless technology standard for e xchanging data o v er short distances using short-w a v elength UHF radio w a v es in the ISM band from 2.4 to 2.485 GHz from fix ed and mobile de vices, and b uilding personal area netw orks (P ANs). In v ented by telecom v endor Ericsson in 1994, it w as originally concei v ed as a wireless alternati v e to RS-232 data cables. It can connect se v eral de vices, o v ercoming problems of synchronization. The uni v ersal filter circuit of Fig. 3 is also t u ne d for Bluetooth applications. The simulation result for the tuning of the filter for Bluetooth application is sho wn in Fig. 7. Figure 7. T uning of Band P ass Filter for Bluetooth Applications 5. CONCLUSION A CMOS-based implementation of multi output current controlled current dif ferencing transconductance am- plifier (MOCCCDT A) w as presented. The performance comparison of MOCCCDT A has been done by performing transient and A C analyses for 180nm, 90nm and 45nm CMOS technology nodes using HSPICE simulations. It w as found that the MOCCCDT A circuit of fers highest bandwidth at 45nm CMOS technology node. A current mode uni- v ersal biquad filter w as then discussed that emplo ys a MOCCCDT A as an acti v e element and tw o grounded capacitors. The filter pro vides lo w-pass, high-pass, band-pass and band-reject responses. Also the tunability of the lo w-pass, high- pass, band-pass and band-reject filter w as analysed by v arying the bias current. Ne xt the tunability of the lter for the Bluetooth application has been discussed. The filter circuit is suitable for high frequenc y Bluetooth applications. IJECE V ol. 6, No. 4, August 2016: 1499 1505 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 1505 REFERENCES [1] P .E. Allen and D.R. Holber g. CMOS analog circuit design. Ne w Y ork: Oxfor d Univer sity Pr ess , 2002. [2] Da vid A. Johns and K en Martin. Analog inte grated circuit design. W ile y India Pvt. Ltd. , 1997. [3] K. Bult. Analog design in deep sub-micron cmos. Pr oc. Eur opean Solid-State Conf , pages 126–132, 2001. [4] J. R. Angulo, R.G. Carv ajal, and A. L. Martin. T echniques for the desi gn of lo w v oltage po wer ef fic ient analog and mix ed signal circuits. 22nd International Confer ence on VLSI Design , 26, No. 27:5–9, Jan. 2009. [5] Lattenber g and Vrba. Filters with current amplifiers for high-speed communication. International Confer ence on Systems and Mobile Communications and Learning T ec hnolo gies , 150, No. 150:23–29, Apr . 2006. [6] H. H. K untman and A. Uygur . Ne w possibilities and trends in circuit design for analog signal processing. International Confer ence on Applied Electr onics , 1, No. 9:5–7, Sept. 2012. [7] Sajai V ir Singh, Sudhanshu Maheshw ari, and Dur g Singh Chauhan. Si n gl e MO-CCCCT A based electronically tunable current tranimpedence mode biquad uni v ersal filter . J ournal of Cir cuits and Systems , 2:1–6, 2011. [8] A. Bhatt . Design and analysis of cmos current con v e yor . J ournal of Information, Knowledg e and Resear c h in ECE , 2, Issue 2, Oct. 2013. [9] J. Sharma, M. S. Ansari , and J. B. Sharma. Electronically tunable resistor -less uni v ersal filter in 0.5v 32nm CNFET. F ifth International Symposium on Electr onic System Design (ISED) , page 206207, Dec. 2014. [10] J. Sharma, M. S. Ansari, and J. B. Sharma. Current-mode electronically tunable resistor -less uni v ersal filter in 0.5v 32nm CNFET. International Confer ence on De vices, Cir cuits and Communications (ICDCCom) , page 16, Sept. 2014. [11] Montree Siripruch yanun and W anai Jaikla. Cmos current controlled current dif ferencing transconductance am- plifier and applications to analog signal processing. International J ournal of Electr onics and Communications (AEU) , 62:277–287, 2007. [12] Anisur Rehman Nasir and S.N.Ahmad. Single CDT A based current- mode uni v ersal filter with grounded capac- itors. International J ournal Of Electr onics Engineering , 4:73–75, 2012. [13] Ajay K umar K ushw ala and Sajal K.P aul. Current mode uni v ersal filter using single CCDDCCT A. J ournal of Cir cuits and Systems , 6:224–236, 2015. [14] Dinesh Prasad, Data Ram Bhaskar , and Mayank Sri v asta v a. Uni v ersal current mode biquad filter using a VDT A. J ournal of Cir cuits and Systems. , 4:29–33, 2013. [15] Raj Senani, Kasim Karam Abdalla, and Data Ram Bhaskar . A state v ariable method for realisation of uni v ersal current mode biquads. J ournal of Cir cuits and Systems , 2:286–292, 2011. BIOGRAPHIES OF A UTHORS Jy oti Sharma is Assistant Professor in the Department of ECE at BIT MESRA, Jaipur Campus with Master of T echnology from NIT , Jaipur . She is pursuing Ph.D. in the field of VLSI Circuit Design from BI T Mesra. Her researches are in fields of electronics, analog systems, VLSI Circuits, Nanotechnology , Current Mode Circuits. She is a member of the IETE(Institution for Electronics and T elecom engineers) Shantanu Chakraborty is currently persuing his under graduate de gree of Bachelor Of Engineer - ing in Electronics and Communication Engineering at BIT MESRA,Jaipur Cam pus. He is presently a student member of the IETE(Institution for Electronics and T elecom engineers) and has acti v ely participated in National Students’ Congress F orum or g anised by IETE at BIT MESRA. He is also acti v ely in v olv ed in the technical committee of the Uni v ersity as a student coordinator .He has in- v olv ed himself in minor project w orks in the institution as a student coordinator . MOCCCDT A-based Curr ent Mode T unable Univer sal Biquad F ilter for ... (Jyoti Sharma) Evaluation Warning : The document was created with Spire.PDF for Python.