Your browser does not support JavaScript!
http://iet.metastore.ingenta.com
1887

access icon free Linearisation technique for low-voltage tuneable Nauta's transconductor in Gm − C filter design

© The Institution of Engineering and Technology
Received 16/05/2017, Accepted 29/12/2017, Revised 28/11/2017, Published 11/01/2018

A low-distortion, low-voltage transconductor based on Nauta's inverter-type transconductor is proposed. The transconductor's core MOSFETs are pushed into a strong inversion region under a low-voltage supply utilizing a level shifter consisting of a linear resistor and a MOSFET current source. The transconductor's linearization relies on summing a decreasing Gm characteristic with an increasing counterpart to obtain an overall flat Gm characteristic. The non-ideal decreasing Gm is exploited from a non-linear behaviour of the triode–MOS current source that restricts a |V GS| increment of the core strongly-inverted MOSFET quartet while its increasing-Gm counterpart found in another weakly-inverted auxiliary MOSFET quartet. The MOSFET current source plays significant role in the linearization process where it has to be in a triode mode of either a strong, weak or moderate inversion region. Simulation results are provided to verify the feasibility of the proposed transconductor with a 5th-order Chebyshev lowpass filter in a 0.18 µm CMOS process. The filter operates under a 0.5 V supply (the ratio V DD/V TH = 1.19) with a continuous bandwidth tuning from 500 kHz to 2.8 MHz. The proposed filter with a nominal 1.4 MHz bandwidth and a 430 mW power consumption renders the two-tone SFDR of 64.9 dB.

Inspec keywords: CMOS integrated circuits; MOSFET circuits; invertors; linearisation techniques; Chebyshev filters; Monte Carlo methods; low-pass filters; triodes; constant current sources

Other keywords: transconductor core MOSFETs; inverted MOSFET quartet; two-tone spurious-free dynamic range; size 0.18 mum; frequency 500 kHz to 2.8 MHz; Gm−C filter design; nonlinear behaviour; total harmonic distortion; strong inversion region; power consumption; CMOS process; tunable MOS current source; voltage level shifter; linearisation technique; triode–MOS current source; fifth-order Chebyshev lowpass filter; power 430 muW; Monte-Carlo analysis; bandwidth 1.4 MHz; passive linear resistor; corner analyses; voltage 0.5 V; low supply voltage; low-distortion low-voltage tuneable Nauta inverter-type transconductor; continuous bandwidth tuning; post-layout simulation

Subjects: Monte Carlo methods; CMOS integrated circuits; Filters and other networks; Vacuum tubes; Power electronics, supply and supervisory circuits

References

    1. 1)
      • 12. Marais, E.: ‘Complex band-pass filter’, US Patent 7 248 103, 24 July 2007.
    2. 2)
      • 6. Nauta, B.: ‘CMOS VHF transconductance-C lowpass filter’, Electron. Lett., 1990, 26, (7), pp. 421–422.
    3. 3)
      • 1. Huang, H., Lee, K.F.: ‘Design of low-voltage CMOS continuous-time filter with on-chip automatic tuning’, IEEE J. Solid-State Circuits, 2001, 36, pp. 1168–1177.
    4. 4)
      • 19. Mahattanakul, J., Khumsat, P., Surakampontorn, W.: ‘Selection of the common-mode feedback network connection of fully differential Gm-C filters’, IET Circuits Devices Syst., 2009, 3, (1), pp. 49–56.
    5. 5)
      • 15. Munoz, F., Torralba, A., Carvajal, R.G., et al: ‘Two new VHF tunable CMOS low-voltage linear transconductors and their application to HF GM-C filter design’. Proc. of IEEE Int. Symp. on Circuits and Systems (ISCAS), 2000, vol. 5, pp. 173–176.
    6. 6)
      • 20. Lee, T.H.: ‘The design of CMOS radio-frequency integrated circuits’ (Cambridge University Press, Cambridge, UK, 2004, 2nd edn.), Chapter 12.
    7. 7)
      • 5. Nauta, B., Seevinck, E.: ‘Linear CMOS transconductance element for VHF filters’, Electron. Lett., 1989, 25, (7), pp. 448–450.
    8. 8)
      • 4. Khumsat, P., Worapishet, A.: ‘A 0.5-V R-MOSFET-C filter design using subthreshold R-MOSFET resistors and OTAs with cross-forword common-mode cancellation technique’, IEEE J. Solid-State Circuits, 2012, 47, pp. 2751–2762.
    9. 9)
      • 17. Gray, P.R., Hurst, P.J., Lewis, S.H., et al: ‘Analysis and design of analog integrated circuits’ (John Wiley & Sons, New York, 2009, 5th edn.), Chapter 1.
    10. 10)
      • 7. Nauta, B.: ‘A CMOS transconductance–C filter technique for very high frequencies’, IEEE J. Solid-State Circuits, 1992, 27, pp. 142–153.
    11. 11)
      • 3. Chatterjee, S., Tsividis, Y.P., Kinget, P.: ‘0.5-V analog circuit techniques and their applications to OTA and filter design’, IEEE J. Solid-State Circuits, 2005, 40, pp. 2373–2387.
    12. 12)
      • 2. Vemulapali, G., Hanumolu, P.K., Kook, Y.J., et al: ‘A 0.8-V accurately tunned linear continuous-time filter’, IEEE J. Solid-State Circuits, 2005, 40, pp. 1972–1977.
    13. 13)
      • 14. Crombez, P., Craninckx, J., Steyaert, M.: ‘A 100 kHz–20 MHz reconfigurable Nauta gm–C biquad lowpass filter in 13 μm CMOS’. Proc. of IEEE Asian Solid-State Conf., 12–14 November 2007.
    14. 14)
      • 11. Park, J.W., Kim, C.S.: ‘Nauta operational transconductance amplifier’, US Patent 7 616 056, 10 November 2009.
    15. 15)
      • 18. Tsividis, Y.: ‘Operation and modeling of the MOS transistor’ (McGraw-Hill, Singapore, 1999, 2nd edn.), Chapter 4.
    16. 16)
      • 13. Vishinsky, A.S.: ‘Self-tuned active bandpass filters’, US Patent 7 400 212, 15 July, 2008.
    17. 17)
      • 9. Guthrie, B., Hughes, J., Sayers, T., et al: ‘A CMOS gyrator low-IF filter for a dual-mode bluetooth/ZigBee transceiver’, IEEE J. Solid-State Circuits, 2005, 40, pp. 1872–1879.
    18. 18)
      • 10. Hughes, J.B.: ‘Balanced transconductor and electronic device’, US Patent 6 680 627, 20 January 2004.
    19. 19)
      • 16. Torralba, A., Carvajal, R.G., Ramírez-Angulo, J., et al: ‘Class AB output stages for low voltage CMOS opamps with accurate quiescent current control by means of dynamic biasing’, Analog Integr. Circuits Signal Process., 2003, 36, pp. 69–77.
    20. 20)
      • 8. Andreani, P., Mattisson, S.: ‘On the use of Nauta's transconductor in low-frequency CMOS gm–C bandpass filters’, IEEE J. Solid-State Circuits, 2002, 37, pp. 114–124.
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-cds.2017.0177
Loading

Related content

content/journals/10.1049/iet-cds.2017.0177
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading
Print this page
This is a required field
Please enter a valid email address