A low voltage low power operational transconductance amplifier (OTA) based on a bulk driven cell and its application to implement a tunable Gm-C filter is presented. The linearity of the OTA is improved by attenuation and source degeneration techniques. The attenuation technique is implemented by bulk driven cell which is used for low supply voltage circuits. The OTA is designed to operate with a 0.9 V supply voltage and consumes 58.8 μW power. A 600 mVppd sine wave input signal at 1 MHz frequency shows total harmonic distortion (THD) better than -40 dB over the tuning range of the transconductance. The OTA has been used to realize a tunable Gm-C low-pass filter with gain tuning from 5 dB to 21 dB with 4 dB gain steps, which results in power consumptions of 411.6 to 646.8 μW. This low voltage filter can operate as channel select filter and variable gain amplifier (VGA) for wireless sensor network (WSN) applications. The proposed OTA and filter have been simulated in 0.18 μm CMOS technology. Corner case and temperature simulation results are also included to forecast process and temperature variation affects after fabrication.
Cite this paper
S. Abbasalizadeh, S. Sheikhaei and B. Forouzandeh, "A 0.9 V Supply OTA in 0.18 μm CMOS Technology and Its Application in Realizing a Tunable Low-Pass Gm-C Filter for Wireless Sensor Networks," Circuits and Systems, Vol. 4 No. 1, 2013, pp. 34-43. doi: 10.4236/cs.2013.41007.
 A. El Mourabit, G. Lu and P. Pittet, “Wide-Linear-Range Subthreshold OTA for Low-Power, Low-Voltage, and Low-Frequency Applications,” IEEE Transactions on Circuits and Systems I, Vol. 52, No. 8, 2005, pp. 1481-1488. doi:10.1109/TCSI.2005.852011
 A. Worapishet and C. Naphaphan, “Current-Feedback Source-Degenerated CMOS Transconductor with Very High Linearity,” Electronics Letters, Vol. 39, No. 7, 2003, pp. 17-18. doi:10.1049/el:20030050
 A. J. López-Martín, J. Ramirez-Angulo, C. Durbha and R. G. Carvajal, “A CMOS Transconductor with Multidecade Tuning Using Balanced Current Scaling in Moderate Inversion,” IEEE Journal of Solid-State Circuits, Vol. 40, No. 5, 2005, pp. doi:10.1109/JSSC.2005.845980
 F. A. P. Barúqui and A. Petraglia, “Linearly Tunable CMOS OTA with Constant Dynamic Range Using Source-Degenerated Current Mirrors,” IEEE Transactions on Circuits and Systems II, Vol. 53, No. 9, 2006, pp. 791-801. doi:10.1109/TCSII.2006.881162
 T.-Y. Lo and C.-C. Hung, “A 1-V 50-MHz Pseudodifferential OTA with Compensation of the Mobility Reduction,” IEEE Transactions on Circuits and Systems II, Vol. 54, No. 12, 2007, pp. 1047-1051.
 K. Kwon, H.-T. Kim and K. Lee, “A 50 -300-MHz Highly Linear and Low-Noise CMOS Gm-C Filter Adopting Multiple Gated Transistors for Digital TV Tuner ICs,” IEEE Transactions on Microwave Theory and Techniques, Vol. 57, No. 2, 2009, pp. 306-313.
 H. Le-Thai, H.-H. Nguyen, H.-N. Nguyen, H.-S. Cho, J.-S. Lee, et al., “An IF Bandpass Filter Based on a Low Distortion Transconductor,” IEEE Journal of Solid-State Circuits, Vol. 45, No. 11, 2010, pp. 2250-2261.
 A. Lewinski and J. S. Martinez, “OTA Linearity Enhancement Technique for High Frequency Applications With IM3 Below -65 dB,” IEEE Transactions on Circuits and Systems II, Vol. 51, No. 10, 2004, pp. 542-548.
 S. Ouzounov, E. Roza, J. A. (Hans) Hegt, G. Weide and A. H. M. van Roermund, “A CMOS V-I Converter with 75-dB SFDR and 360-μW Power Consumption,” IEEE Journal of Solid-State Circuits, Vol. 40, No. 7, 2005, pp. 1527-1532. doi:10.1109/JSSC.2005.847496
 T.-Y. Lo and C.-C. Hung, “A 40-MHz Double Differential-Pair CMOS OTA with -60-dB IM3,” IEEE Transactions on Circuits and Systems I, Vol. 55, No. 1, 2008, pp. 258-265. doi:10.1109/TCSI.2007.910747
 C. I. Lujan-Martinez, R. G. Carvajal, A. Torralba, A. J. Lopez-Martin, J. Ramirez-Angulo, et al., “Low-Power Baseband Filter for Zero-Intermediate Frequency Digital Video Broadcasting Terrestrial/Handheld Receivers,” IET Circuits, Devices and Systems, Vol. 3, No. 5, 2009, pp. 291-301. doi:10.1049/iet-cds.2008.0326
 U. Yodprasit and C. C. Enz, “A 1.5-V 75-dB Dynamic Range Third-Order Gm-C Filter Integrated in a 0.18-μm Standard Digital CMOS Process,” IEEE Journal of Solid-State Circuits, Vol. 38, No. 7, 2003, pp. 1189-1197.
 S. Han, “A Novel Tunable Transconductance Amplifier Based on Voltage-Controlled Resistance by MOS Transistors,” IEEE Transactions on Circuits and Systems II, Vol. 53, No. 8, 2006, pp. 662-666.
 E. Sánchez-Sinencio and J. Silva-Martinez, “CMOS Transconductance Amplifiers, Architectures and Active Filters: A Tutorial,” IEEE Proceedings Circuits, Devices and Systems, Vol. 147, No. 1, 2000, pp. 3-12.
 J. M. Carrillo ,G. Torelli, R. P. Aloe, J. M. Valverde and J. F. Duque-Carrillo, “Single-Pair Bulk-Driven CMOS Input Stage: A Compact Low-Voltage Analog Cell for Scaled Technologies,” Integration, the VLSI journal, Vol. 43, No. 3, 2010, pp. 251-257.
 F. Rezaei and S. J. Azhari, “Ultra Low Voltage, High Performance Operational Transconductance Amplifier and Its Application in A Tunable Gm-C Filter,” Microelectronics Journal, Vol. 42, No. 6, 2011, pp. 827-836.
 J. M. Carrillo, G. Torelli and J. F. Duque-Carrillo, “Transconductance Enhancement in Bulk-Driven Input Stages and Its Applications,” Analog Integrated Circuits and Signal Processing, Vol. 68, No. 2, 2011, pp. 207-217.
 R. G. Carvajal, J. R. Angulo, A. J. López-Martín, A. Torralba, J. Antonio Gómez Galán, et al., “The Flipped Voltage Follower: A Useful Cell for Low-Voltage Low-Power Circuit Design,” IEEE Transactions on Circuits and Systems I, Vol. 52, No. 7, 2005, pp. 1276-1291.
 T.-Y. Lo and C.-C. Hung, “A 250 MHz Low Voltage Low-Pass Gm-C Filter,” Analog Integrated Circuits and Signal Processing, Vol. 71, No. 3, 2012, pp. 465-472.
 Y. H. Kong, H. Yang, M. Jiang, S. Z. Xu and H. Z. Yang, “Low-Voltage Transconductor with Wide Input Range and Large Tuning Capability,” Tsinghua Science and Technology, Vol. 16, No. 1, 2011, pp. 106-112.
 S. S. Rajput and S. S. Jamuar, “Low Voltage Analog Circuit Design Techniques,” IEEE Circuits and Systems Magazine, Vol. 2, No. 1, 2002, pp. 24-42.
 N.-J. Oh and S.-G. Lee, “Building a 2.4-GHz Radio Transceiver Using IEEE 802.15.4,” IEEE Circuits & Devices Magazine, Vol. 21, No. 6, 2005, pp. 43-51.
 A. Tajalli and Y. Leblebici, “Linearity Improvement in Biquadratic Transconductor-C Filters,” Electronics Letters, Vol. 43, No. 24, 2007, pp. 1360-1362.
 M. S. Oskooei, N. Masoumi, M. Kamarei and H. Sjoland, “A CMOS 4.35-mW + 22-dBm IIP3 Continuously Tunable Channel Select Filter for WLAN/WiMAX Receivers,” IEEE Journal of Solid-State Circuits, Vol. 46, No. 6, 2011, pp. 1382-1391. doi:10.1109/JSSC.2011.2120670
 T.-Y. Lo, C.-C. Hung and M. Ismail, “A Wide Tuning Range Gm-C Filter for Multi-Mode CMOS Direct-Conversion Wireless Receivers,” IEEE Journal of Solid-State Circuits, Vol. 44, No. 9, 2009, pp. 2515-2524.