Re-configurable Switched Capacitor Sigma-Delta Modulator for MEMS Microphones in Mobiles

  • M. Grassi
  • F. Conso
  • G. Rocca
  • P. Malcovati
  • A. Baschirotto
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 457)


This paper presents a reconfigurable discrete-time audio Sigma-Delta modulator implemented in 0.18-µm CMOS technology. The 600 µm × 400 µm core area SD modulator is based on a 2 + 2 MASH architecture, and features several different operating modes in which noise-shaping order, number of output word bits, sampling rate, and bandwidth can be programmed ad hoc. By design, the power consumption is minimized for the selected operating mode. The achieved performance ranges from 99-dB DR with 4th-order noise shaping and full standard audio bandwidth, while consuming 0.97 mW down to 85-dB DR with second order noise shaping over reduced bandwidth for vocal control operation, while consuming 100 µW. The developed device can be used either to read-out different sources (microphones) or to operate in different modes within the same system (i.e. with the same microphone in different scenarios). The trade-off between performance and re-configurability is the key element of this work.


MASH Sigma-Delta Data converter Microphones Re-configurable MEMS 


  1. 1.
    Badami, K.M.H., et al.: A 90-nm CMOS, 6-mW power-proportional acoustic sensing frontend for voice activity detection. IEEE J. Solid-State Circ. 51(1), 291–302 (Jan. 2016)Google Scholar
  2. 2.
    Park, H., et al.: A 0.7-V 870-mW digital-audio CMOS sigma-delta modulator. IEEE J. Solid-State Circ. 44(4), 1078–1088 (Apr. 2009)Google Scholar
  3. 3.
    Yang, Z., et al.: A 0.5-V 35-mW 85-dB DR double-sampled DS modulator for audio applications. IEEE J. Solid-State Circ. 47(3), 722–735 (Mar. 2012)Google Scholar
  4. 4.
    Christen, T.: A 15-bit 140-mW scalable-bandwidth inverter-based DS modulator for a MEMS microphone with digital output. IEEE J. Solid-State Circ. 48(7), 1605–1614 (July 2013)Google Scholar
  5. 5.
    Yang, Y.Q., et al.: A 114-dB 68-mW chopper-stabilized stereo multibit audio ADC in 5.62 mm2. IEEE J. Solid-State Circ. 38(12), 2061–2068 (Dec. 2003)Google Scholar
  6. 6.
    Luo, H., et al.: A 0.8-V 230-mW 98-dB DR inverter-based SD modulator for audio applications. IEEE J. Solid-State Circ. 48(10), 2430–2441 (Oct. 2013)Google Scholar
  7. 7.
    De Berti, C., et al.: A 106.7-dB DR, 390-mW CT 3rd-order SD modulator for MEMS microphones. In: Proc. ESSCIRC, 209–212 (Sep. 2015)Google Scholar
  8. 8.
    Grassi, M., Conso, F., Rocca, G., Malcovati, P., Baschirotto, A.: A multi-mode SC audio Sigma-Delta Modulator for MEMS microphones with reconfigurable power consumption, noise-shaping order, and DR. In: 42nd European Solid State Conference Proceedings - ESSCIRC 2016, Lausanne, 12–15 September 2016, pp. 245–248, IEEE (2016)Google Scholar

Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  • M. Grassi
    • 1
  • F. Conso
    • 2
  • G. Rocca
    • 2
  • P. Malcovati
    • 1
  • A. Baschirotto
    • 3
  1. 1.Dept. of Electrical, Computer, and Biomedical EngineeringUniversity of PaviaPaviaItaly
  2. 2.Epcos-Europe-TDKCopenhagenDenmark
  3. 3.Dept. of PhysicsUniversity of Milano-BicoccaMilanItaly

Personalised recommendations