고주파용 필터구현을 위한 개선된 CMFB회로를 이용한 CMOS Op-amp 설계

A CMOS Op-amp Design of Improved Common Mode Feedback(CMFB) Circuit for High-frequency Filter Implementation

  • 임대성 (전북대학교 전기공학과) ;
  • 최영재 (전북대학교 전기공학과) ;
  • 이명수 (전북대학교 전기공학과) ;
  • 김동용 (전북대학교 전기공학과)
  • 발행 : 1993.07.18

초록

A fully balanced differential amplifier can achieve high-gain wide-bandwidth characteristics. And also, Offset PSRR, CMRR and Noise performance of that are excellent, but these merits can be achieved only when the architecture holds fully balanced. Commonly, the fully balanced differential amplifier has a common mode feedback(CMFB) circuit in order to maintain the balance. This paper presents improved characteristics of the CMFB circuit and designs the wide-bandwidth CMOS Op-amp. The unity gain bandwidth of this Op-amp is 50MHz with the load capacitor 2pF, and the value of phase margin is $85^{\circ}$.

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