Negative current feedback OTA with application to 250 MHz Gm-C filter
Abstract
A 4th-order low-pass Gm-C filter for high speed wireless/wireline system is realized in 0.18 μm CMOS process. The high speed filter is designed based on operational transconductance amplifier (OTA) biquad sections. As well known, large transconductance is required for high speed applications, and thus the conventional source degeneration topology, which operates with the trade-off between linearity and transconductance, should be improved. In this paper, the proposed OTA uses negative current feedback topology to maintain linearity while increasing transconductance for high speed application, and a 4th-order low-pass filter is realized by using the OTA as a building block. Fabricated in 0.18 μm CMOS technology, the −3 dB filter frequency response at 250 MHz is obtained. The measured HD3 performance is about −40 dB while the filter consumes 32 mW power at a 1.8 V supply voltage.
Keywords
OTA Filter HD3Notes
Acknowledgments
The authors would like to thank the National Chip Implementation Center of Taiwan for supporting the chip fabrication.
References
- 1.Ismail, M., & Fiez, T. (1994). Analog VLSI signal and information processing. New York: McGraw-Hill.Google Scholar
- 2.Hung, C. C., Halonen, K. A., Ismail, M., Porra, V., & Hyogo, A. (1997). A low-voltage, low-power CMOS fifth-order elliptic GM-C filter for baseband mobile, wireless communication. IEEE Transactions on Circuits and Systems for Video Technology, 7, 584–593.CrossRefGoogle Scholar
- 3.De Lima, J. A., & Dualibe, C. (2001). A linearly tunable low voltage CMOS transconductor with improved common-mode stability and its application to gm-C filters. IEEE Transactions on Circuits and Systems Part II, 48(7), 649–660.CrossRefGoogle Scholar
- 4.Lo, T. Y., Hung, C. C., & Ismail, M. (2009). A wide tuning range Gm-C filter for multi-mode direct-conversion wireless receivers. IEEE Journal of Solid-State Circuits, 44(9), 2515–2524.CrossRefGoogle Scholar
- 5.S. Hori, T. Maeda, N. Matsuno, & H. Hida. (2004). Low-power widely tunable Gm-C filter with an adaptive DC-blocking, triode-biased MOSFET transconductor. In Proceedings ESSCIRC (pp. 99–102).Google Scholar
- 6.De Matteis, M., D’Amico, S., & Baschirotto, A. (2009). A 0.55 V 60 dB-DR fourth-order analog baseband filter. IEEE Journal of Solid-State Circuits, 44(9), 2525–2534.CrossRefGoogle Scholar
- 7.S. D’Amico, M. De Matteis, & A. Baschirotto. (2008). A 6th-order 100 μA 280 MHz source-follower-based single-loop continuous-time filter. In IEEE ISSCC (pp. 12–14).Google Scholar
- 8.Carvajal, R. G., Ramírez-Angulo, J., López-Martín, A. J., Torralba, A., Galán, J. A. G., Carlosena, A., et al. (2005). The flipped voltage follower: A useful cell for low-voltage low-power circuit design. IEEE Transactions Circuits Systems I, 52(7), 1276–1291. (Reg. Papers).CrossRefGoogle Scholar
- 9.Arai, T., Koyama, M., Tanimoto, H. & Yoshida, Y. (1993). A 2.5 V active lowpass filter using all-npn gain cells with a l-Vpp linear input range. In IEEE ISSCC (pp. 112–113).Google Scholar
- 10.Johns, D. A., & Martin, K. (1997). Analog integrated circuit design, Chapter 14. New York: Wiley.Google Scholar
- 11.Nader Mohieldin, A., Sánchez-Sinencio, E., & Silva-Martínez, J. (2003). A fully balanced pseudo-differential OTA with common-mode feedforward and inherent common-mode feedback detector. IEEE Journal of Solid-State Circuits, 38(4), 663–668.CrossRefGoogle Scholar
- 12.Pandey, P., Silva-Martinez, J., & Liu, X. (2006). A CMOS 140-mW fourth-order continuous-time low-pass filter stabilized with a Class AB common-mode feedback operating at 550 MHz. IEEE Transactions on Circuits and Systems Part 1, 53(4), 811–820. (Reg. Papers).CrossRefGoogle Scholar