Continuous-Time Common-Mode Feedback for High-Speed Switched-Capacitor Networks Academic Article uri icon

abstract

  • This paper deals with the design of a continuous-time common-mode feedback (CMFB) for switched-capacitor networks. Its reduced input capacitance decreases the capacitive load at the output of the fully differential amplifier, improving its achievable gain-bandwidth (GBW) product and slew rate. This topology is more suitable for high-speed switched-capacitor applications when compared to a conventional switched-capacitor CMFB, enabling operation at higher clock frequencies. Additionally, it provides a superior rejection to the negative power supply noise (PSRR -). The performance of the CMFB is demonstrated in the implementation of a second-order 10.7-MHz bandpass switched-capacitor filter and compared with that of an identical filter using the conventional switched-capacitor CMFB (SC-CMFB). The filter using the continuous-time CMFB reduces the error due to finite GBW and slew rate to less than 1% for clock frequencies up to 72 MHz while providing a dynamic range of 59 dB and a PSRR - > 22 dB. Both circuits were fabricated in 0.35-μm CMOS technology. © 2005 IEEE.

altmetric score

  • 6

author list (cited authors)

  • Hernandez-Garduno, D., & Silva-Martinez, J.

citation count

  • 28

publication date

  • August 2005