一种用于流水线ADC中的全差分运算放大器  

An Fully Differential Operational Amplifier for Pipelined A/D Converter

作　　者：刘俊[1] 吕坚[1] 蒋亚东[1] 袁凯[1] 

机构地区：[1]成都电子科技大学电子薄膜与集成器件国家重点实验室,成都610054

出　　处：《微处理机》2009年第2期28-30,34,共4页Microprocessors

基　　金：国家杰出青年基金(60425101)

摘　　要：提出了一种高增益、高稳定性全差分运算放大器,采用稳定的共模反馈结构。该运算放大器由一个折叠式运放和一个共源增益级构成,并对运放和共模反馈环路都进行了密勒补偿,实现了运放和共模反馈环路,同时具有高增益和足够的相位裕度。经仿真可得,负载为5pf时,运放的开环增益97.64dB,单位增益带宽27.74MHz,相位裕度86.87,°输出摆幅5.1V,建立时间80ns(90%),共模反馈环路同样具有高增益和高相位裕度,非常适合用于高精度流水线式A/D转换器中的级间增益电路和采样保持电路。A high gain and high stability fully differential operational amplifier （op amp ） is presented. A stable common-mode feedback circuit is used in the op amp.The amplifier consists folded- cascode input stage followed by a common - source output gain stage. The amplifier and the common - mode feedback ciucuit are compensated with Miller compensation in order to both of them have high gain and sufficient phase margin. The simulation result shows that the proposed op amp achieved a DC open - loopgain of 97.64dB ,a unity gain bandwidth of 27.74MHz, a phase margin of 86.87° ,a output swing of 5.1V,a setting time of 80ns（5pf load）.And the common -mode feedback loop achieves a high DC open - loop gain and high phase margin. This op amp is appropriate to be used in the inter - stage gain circuit and sample - hold circuit of high accuracy pipeline AID converter.

关 键 词：全差分 运算放大器 折叠式共源共栅 共模反馈 

分 类 号：TN4[电子电信—微电子学与固体电子学]