Filters & Tuning

Filters are system that can be used to manipulate the frequency spectrum of signals and they are essential in many different applications. For example, they can be used to band-limit signals and noise in data conversion systems or communication systems, provide equalizations in hard disk driver systems or for transmission lines and cables, select band, reject image, and detect signals in RF communication systems, etc. There are different types of analog filters. While passive filters comprise passive components such as resistors, capacitors, and inductors, active filters use active devices such as operational amplifiers (OPAMP) and/or operational transconductance amplifiers (OTA). Active filters can also classified into Active-RC, Switched-Capacitor, Gm-C, and LC filters, etc. While Active-RC and Switched-Capacitor filters are suitable for low to medium frequency applications, Gm-C and LC filters can be used in medium to high frequency systems. Because of the process and temperature variations, automatic frequency and/or quality factor tuning schemes are needed for high performance systems.

An example of the kind of research work going on in this group includes a 60mW, 200MHz continuous time 7th order linear phase filter with on-chip automatic tuning system. A full CMOS 7th order linear phase filter based on gm-C biquads with a –3 dB frequency of 200 MHz was realized in 0.35 mm CMOS process. The linear Operational Transconductance Amplifier is based on complementary differential pairs in order to achieve both low-distortion figures and high-frequency operation. The Common-Mode FeedBack (CMFB) employed takes advantage of the filter architecture; incorporating the load capacitors into the CMFB loop improves further its phase margin. A very simple automatic tuning system corrects the filter deviations due to process parameter tolerances and temperature variations. 

 Journal Publications

Jose L. Ausin, J. Francisco Duque-Carrillo, Guido Torelli, E. Sanchez-Sinencio, "Switched-Capacitor Circuits With Periodical Nonuniform Individual Sampling", IEEE Transactions on Circuits and Systems - II: Analog and Digital Signal Processing, Volume: 50 Issue: 8, August 2003, page(s): 404-414

Hengsheng Liu; Karsilayan, A.I., "An accurate automatic tuning scheme for high-Q continuous-time bandpass filters based on amplitude comparison",  IEEE Transactions on Circuits and Systems - II: Analog and Digital Signal Processing. Volume: 50 Issue: 8, August 2003, page(s): 415- 423

Dulger, F.; Sanchez-Sinencio, E.; Silva-Martinez, J., "A 1.3-V 5-mW fully integrated tunable bandpass filter at 2.1 GHz in 0.35-/spl mu/m CMOS," IEEE Journal of Solid-State Circuits, Volume :38 Issue:6, June 2003, Page(s): 918- 928

Becker-Gomez, A., Cilingiroglu, U., Silva-Martinez, J, "Compact sub-hertz ota-c filter design with interface-trap charge pump," IEEE Journal of Solid-State Circuits, Volume :38 Issue:6, June 2003, Page(s): 929- 934.

Mohieldin, A.N., Sanchez-Sinencio, E., Silva-Martinez, J., "A fully balanced pseudo-differential OTA with common-mode feedforward and inherent common-mode feedback detector", IEEE Journal of Solid-State Circuits , Volume: 38 Issue: 4 , Apr 2003 ,  Page(s): 663 -668

Kallam, P., Sanchez-Sinencio, E., Karsilayan, A.I., "An enhanced adaptive Q-tuning scheme for a 100-MHz fully symmetric OTA-based bandpass filter",IEEE Journal of State Circuits , Volume: 38 Issue: 4 , Apr 2003,  Page(s): 585 -593

Silva-Martinez, J., Adut, J., Rocha-Perez, J.M., Robinson, M., Rokhsaz, S., "A 60-mW 200-MHz continuous-time seventh-order linear phase filter with on-chip automatic tuning system", IEEE Journal of Solid-State Circuits , Volume: 38 Issue: 2 , Feb 2003 Page(s): 216 -225

J. L. Ausνn, J. F. Duque-Carrillo, G. Torelli, R. Pιrez-Aloe, E. Sαnchez-Sinencio, "High-Selectivity Switched-Capacitor Bandpass Filter with Quasi-Continuous Quality Factor Tunability", Analog Integrated Circuits and Signal Processing 33(2): 117-126; Nov 2002

Sumesaglam, T., Karsilayan, A.I., “Digital tuning of high-order high-Q continuous-time filters ,” Electronics Letters , Volume: 38, Issue: 19 , Sept. 2002, Page(s): 1076 –1078

Cilingiroglu, U., Dake, L.E., “Rank-order filter design with a sampled-analog multiple-winners-take-all core ,” IEEE Journal of Solid-State Circuits , Volume: 37, Issue: 8 , Aug 2002, Page(s): 978 -984

Veeravalli, A., Sanchez-Sinencio, E., Silva-Martinez, J., "A CMOS transconductance amplifier architecture with wide tuning range for very low frequency applications", IEEE Journal of Solid-State Circuits , Volume: 37 Issue: 6 , Jun 2002,  Page(s): 776 -781

Veeravalli, A., Sanchez-Sinencio, E., Silva-Martinez, J., "Transconductance amplifier structures with very small transconductances: a comparative design approach", IEEE Journal of Solid-State Circuits , Volume: 37 Issue: 6 , Jun 2002, Page(s): 770 -775

Solis-Bustos, S., Silva-Martinez, J., Maloberti, F., Sanchez-Sinencio, E., “A 60-dB dynamic-range CMOS sixth-order 2.4-Hz low-pass filter for medical applications ,” IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing , Volume: 47, Issue: 12 , Dec 2000, Page(s): 1391 –1398

Sanchez-Sinencio, E., Silva-Martinez, J., “CMOS transconductance amplifiers, architectures and active filters: a tutorial ,” IEE Proceedings- Circuits, Devices and Systems , Volume: 147, Issue: 1 , Feb 2000, Page(s): 3 –12

Stevenson, J.-M., Sanchez-Sinencio, E., “An accurate quality factor tuning scheme for IF and high-Q continuous-time filters ,” IEEE Journal of Solid-State Circuits , Volume: 33, Issue: 12 , Dec 1998, Page(s): 1970 –1978

Perez-Aloe, R., Duque-Carrillo, J.F., Sanchez Sinencio, E., Valverde, J.M., Torelli, G., Reyes, A.H., Maloberti, F., “Programmable time-multiplexed switched-capacitor variable equalizer for arbitrary frequency response realizations ,” IEEE Journal of Solid-State Circuits , Volume: 32, Issue: 2 , Feb 1997, Page(s): 274 –278

Smith, S.L., Sanchez-Sinencio, E., “Low voltage integrators for high-frequency CMOS filters using current mode techniques ,” IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing , Volume: 43, Issue: 1 , Jan 1996, Page(s): 39 –48 

Karsilayan, A.I., Tan, M.A., “Current-mode tunable integrator for low voltage applications ,” Electronics Letters , Volume: 31, Issue: 18 , 31 Aug 1995, Page(s): 1525 -1526 

 Conference Publications

Emira, A.; Sanchez-Sinencio, E., "A low-power CMOS complex filter for bluetooth with frequency tuning", Circuits and Systems, 2003. ISCAS '03. Proceedings of the 2003 International Symposium on , Volume: 1 , May 25-28, 2003 Page(s): 489 -492

Kallam, P., Sanchez-Sinencio, E., Karsilayan, A.I., “An improved Q-tuning scheme and a fully symmetric OTA,” IEEE International Symposium on Circuits and Systems, 2002. ISCAS 2002 , Volume: 5 , 2002, Page(s): V-165 -V-168 vol.5.

Ausin, J.L., Perez-Aloe, R., Duque-Carrillo, J.F., Torelli, G., Sanchez-Sinencio, E., “High-selectivity SC filters with continuous digital Q-factor programmability,” IEEE International Symposium on Circuits and Systems, 2002. ISCAS 2002 , Volume: 4 , 2002, Page(s): IV-631 -IV-634 vol.4

Becker-Gomez, A., Cilingiroglu, U., Silva-Martinez, J., “Compact sub-hertz OTA-C filter design with mos interface-trap charge pump,” The 2002 45th Midwest Symposium on Circuits and Systems, 2002. MWSCAS-2002, Volume: 3 , 2002, Page(s): 145 -148

Mingdeng Chen, Mohieldin, A.N., Silva-Martinez, J., "Linearized OTAs for high-frequency continuous-time filters: a comparative study ,” The 2002 45th Midwest Symposium on Circuits and Systems, 2002. MWSCAS-2002., Volume: 3 , 2002 Page(s): 149 -152

Mingdeng Chen, Silva-Martinez, J., Rokhsaz, S., Robinson, M., “A 1.8V CMOS, 80-200MHz continuous-time 4th order 0.05/spl deg/ equiripple linear phase filter with automatic tuning system,” IEEE International Symposium on Circuits and Systems, 2002. ISCAS 2002 , Volume: 5 , 2002, Page(s): V-173 -V-176 vol.5

Adut, J., Silva-Martinez, J., “A high-Q, switched-capacitor filter with reduced capacitance spread using a randomized nonuniform sampling technique,” IEEE International Symposium on Circuits and Systems, 2002. ISCAS 2002 , Volume: 4 , 2002, Page(s): IV-449 -IV-452 vol.4

Hengsheng Liu, Karsilayan, A.I., “Frequency and Q tuning of active-LC filters,” The 2002 45th Midwest Symposium on Circuits and Systems, 2002. MWSCAS-2002 , Volume: 2 , 2002 , Page(s): 65 -68

Karsilayan, A.I., Sumesaglam, T., “Digital tuning of continuous-time high-Q filters,” IEEE International Symposium on Circuits and Systems, 2002. ISCAS 2002 , Volume: 5 , 2002, Page(s): V-601 -V-604 vol.5

Karsilayan, A.I., Sung-Ling Huang, De Lima, J.A., “Automatic tuning of linearly tunable high-Q filters,” IEEE International Symposium on Circuits and Systems, 2002. ISCAS 2002 , Volume: 5 , 2002, Page(s): V-177 -V-180 vol.5

Hengsheng Liu, Karsilayan, A.I., “An automatic tuning scheme for high frequency bandpass filters ,” IEEE International Symposium on Circuits and Systems, 2002. ISCAS 2002 , Volume: 3 , 2002, Page(s): III-551 -III-554 vol.3

Wang, L., Embabi, S.H.K., Sanchez-Sinencio, E., “1.5 V 5.0 MHz switched capacitor circuits in 1.2 ΅m CMOS without voltage bootstrapper,” IEEE Conference on Custom Integrated Circuits, 2001 , 2001, Page(s): 17 –20

Lopez-Martinez, A., Antonio-Chavez, R., Silva-Martinez, J., “A 150 MHz continuous-time seventh order 0.05° equiripple linear phase filter with automatic tuning system,” The 2001 IEEE International Symposium on Circuits and Systems, 2001. ISCAS 2001 , Volume: 1 , 6-9 May 2001, Page(s): 156 -159 vol. 1

Lopez-Martinez, A., Antonio-Chavez, R., Silva-Martinez, J., “A full CMOS 150 MHz OTA-C 7th order linear phase filter,” Proceedings of the IEEE 2nd Dallas CAS Workshop on Low Power/Low Voltage Mixed-Signal Circuits and Systems, 2001. (DCAS-01) , 2001, Page(s): P11 -P14 

Silva-Martinez, J., “Design issues for UHF OTA-C filter realizations,” 2001 Southwest Symposium on Mixed-Signal Design, 2001, SSMSD, 2001 , Page(s): 93 -98

Silva-Martinez, J., Baez-Lopez, D., Gutierrez-Chave, G., “Design techniques for high-swing SC bandpass filters using telescopic OTA's,” Proceedings of the 44th IEEE 2001 Midwest Symposium on Circuits and Systems, 2001. MWSCAS 2001 , Volume: 1 , 2001, Page(s): 88 -90 vol.1

Cilingiroglu, U., Dake, L.E., “A sampled-analog rank-order-filter architecture,” The 8th IEEE International Conference on Electronics, Circuits and Systems, 2001. ICECS 2001 , Volume: 1 , 2001,Page(s): 173 -176 vol.1

Diaz-Sanchez, A., Ramirez-Angulo, J., Lopez, A., Sanchez-Sinencio, E., “A fully parallel CMOS analog median filter,” The 2000 IEEE International Symposium on Circuits and Systems, 2000, ISCAS, 2000 ,Geneva, Volume: 2 , 2000 Page(s): 593 -596 vol.2

Ausin, J.L., Duque-Carillo, J.F., Torelli, G., Sanchez-Sinencio, E., Maloberti, F., “Periodical nonuniform individually sampled switched-capacitor circuits,” The 2000 IEEE International Symposium on Circuits and Systems, 2000, ISCAS, 2000, Geneva, Volume: 5 , 2000, Page(s): 449 -452 vol.5

Dake, T.L.E., Cilingiroglu, U., “Rank-order filter using multiple-winners-take-all,” Proceedings of the 43rd IEEE Midwest Symposium on Circuits and Systems, 2000 , Volume: 1 , 2000, Page(s): 482 -485 vol.1