A Rail-to-Rail CMOS Op-amp with Constant Gain by Using Output Common Mode Current Compensation

출력 단 공통모드 전류 보상으로 일정한 이득을 갖는 Rail-to-Rail CMOS 연산증폭기

  • Lee, Dong-Geon (Electronics and Information Engineering Chonbuk National University) ;
  • Jeong, Hang-Geun (Electronics and Information Engineering Chonbuk National University)
  • 이동건 (전북대학교 전자정보공학부) ;
  • 정항근 (전북대학교 전자정보공학부)
  • Published : 2008.06.18

Abstract

This paper presents an output common mode current compensation method to achieve both constant Gm and constant gain. A conventional rail-to-rail CMOS op-amp with constant Gm was designed by using complementary differential input stage and current compensation skills. But it doesn't operate constant gain, because of output resistance variation. With $0.18{\mu}m$ CMOS process, the simulation results show that the differential gain variation can achieve less than 1.3dB. And a 60dB gain, a 13.5MHz unity gain-frequency, and 1mW power consumption, when operating at 1.8V and 10pF load.

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