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A 0.5 V bulk-input OTA with improved common-mode feedback for low-frequency filtering applications

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Abstract

This paper presents the design of a two-stage pseudo-differential operational transconductance amplifier (OTA) and its application in low-frequency continuous time filters. The OTA was designed in a 0.18 μm, 0.45 V V T CMOS process. An improved bulk-mode common-mode feedback (CMFB) circuit has been designed which does not load the OTA compared to prior art. A self cascode load structure and partial positive feedback provide higher gain. The bulk terminals of all transistors have been biased to lower their threshold voltages (VT) and maximize signal swing. The OTA operates at a supply voltage of 0.5 V and consumes only 28 μW of power. Rail-to-rail input is made possible by using the transistor’s bulk terminal as the input. For a load of 20 pF the OTA has a measured DC gain of 63 dB and a gain-bandwidth product of 570 kHz. To demonstrate the use of the OTA in practical circuits, three active RC filters were designed: a 10 kHz Butterworth filter, a 10 kHz Bessel filter, and a 2.5 kHz Tschebycheff filter.

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References

  1. Yan, S., & Sanchez-Sinencio, E. (2000) Low voltage analog circuit design techniques: A tutorial. IEICE Transactions on Fundamentals, E83(2), 179–196.

    Google Scholar 

  2. Rajput, S. S., & Jamuar, S. S. (2002). Low voltage analog circuit design techniques. IEEE Circuits and Systems Magazine, 2(1), 24–42 (First Quarter).

    Article  Google Scholar 

  3. Blalock, B. J., Allen, P. E., & Rincon-Mora, G. A. (1998). Designing 1-V Op Amps using standard digital CMOS technology. IEEE TCAS II, 45(45), 769–780.

    Google Scholar 

  4. Chatterjee, S., Tsividis, Y., & Kinget, P. (2005). 0.5-V Analog circuit techniques and their application in OTA and filter design. IEEE JSSC, 40(12), 2373–2387.

    Google Scholar 

  5. Chatterjee, S., Tsividis, Y., & Kinget, P. (2004). A 0.5-V bulk-input fully differential operational transconductance amplifier. In Proc. 30th ESSCIRC, pp. 147–150, Sep. 2004.

  6. Ferreira, L., Pimenta, T., & Moreno, R. (2007). An ultra-low-voltage ultra-low-power CMOS miller OTA with rail-to-rail inpu/output swing. IEEE TCAS II, 54(10), 843–847.

    Google Scholar 

  7. Galup-Montoro, C., Schneider, M., & Loss, I. (1994). Series-parallel association of FET’s for high gain and high frequency applications. IEEE JSSC, 29, 1094–1101.

    Google Scholar 

  8. Chen, M. (2003) Low-voltage, low-power circuits for data communication systems. Dissertation. http://handle.tamu.edu/1969.1/1585, Available online.

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Authors and Affiliations

  1. Tufts University, Medford, MA, USA

    Michael Trakimas & Sameer Sonkusale

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  1. Michael Trakimas
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  2. Sameer Sonkusale
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Correspondence to Michael Trakimas.

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Trakimas, M., Sonkusale, S. A 0.5 V bulk-input OTA with improved common-mode feedback for low-frequency filtering applications. Analog Integr Circ Sig Process 59, 83–89 (2009). https://doi.org/10.1007/s10470-008-9236-z

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  • DOI: https://doi.org/10.1007/s10470-008-9236-z

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