Journal of South China University of Technology (Natural Science Edition) ›› 2017, Vol. 45 ›› Issue (1): 42-47.doi: 10.3969/j.issn.1000-565X.2017.01.006

• Electronics, Communication & Automation Technology • Previous Articles     Next Articles

Multi-Stage Operational Amplifier for Broadband Δ-Σ ADC

XU Ken CAI Min HE Xiao-yong   

  1. School of Electronic and Information Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China
  • Received:2016-04-01 Revised:2016-06-03 Online:2017-01-25 Published:2016-12-01
  • Contact: 蔡敏( 1955-) ，男，教授，博士生导师，主要从事专用集成电路设计研究． E-mail:admincai@scut.edu.cn
  • About author:徐肯( 1980-) ，男，博士生，工程师，主要从事射频及混合信号集成电路研究．E-mail: xuken@ 126．com
  • Supported by:
    Supported by the National Science and Technology Major Project of China( 2010ZX03001-004-03)

PDF

94

Abstract:

In order to improve the in-band gain and bandwidth of operational amplifiers,a four-stage operational amplifier of the broadband Δ-Σ ADC used in long-term evolution receivers is proposed.In the operational amplifier,a hybrid frequency compensation scheme combining feedforward Gm-C and Miller technique is adopted to ensure the stability.Then,a high-performance four-stage operational amplifier is designed in 0.13 μm 1P6M CMOS technology,and it is applied to the broadband Δ-Σ ADC.Test results show that ( 1) with a power supply of 1.5V,the operational amplifier achieves a unity gain bandwidth of 442MHz,a DC gain of 72.8dB and a slew rate of 101V/μs; ( 2) with the same bandwidth and power dissipation,the in-band ( 0 ～ 10MHz) gain of the proposed amplifier is 6 dB more than that of the traditional two-stage operational amplifier; and ( 3) in a signal bandwidth of 10MHz,the broadband Δ-Σ ADC adopting the proposed amplifier achieves a SNR of 68 dB and a SFDR of 78 dB.

Key words: operational amplifiers, multi-stage, frequency compensation, broadband amplifiers, sigma-delta modulation, analog-to-digital conversion

CLC Number: