摘要
基于0.18μm CMOS工艺,设计了一种3.3 V低压轨对轨(Rail-to-Rail)运算放大器。该运算放大器的输入级采用3倍电流镜控制的互补差分对结构,实现了满电源幅度的输入输出和恒输入跨导;输出级采用前馈式AB类输出控制电路,保证了轨对轨的输出摆幅以及较强的驱动能力。仿真结果表明,直流开环增益为120 dB,单位增益带宽为5.98 MHz,相位裕度为66°,功耗为0.18 mW,在整个共模范围内输入级跨导变化率为2.45%。
A Rail-to-Rail operational amplifier is designed with 0.18μm CMOS technology at 3.3 V single power supply. Its input stage is a complementary differential pair controlled by three-times current mirror to realize Rail-to-Rail common mode input range and constant trans-conductance,while the output stage employs a feed-forward biased class-AB control circuit, which ensures Rail-to-Rail output swing and strong driving capability. The simulation results indicate that the operational amplifier has achieved open loop DC gain of 120 dB, unit gain bandwidth of 5.98 MHz, phase margin of 66 degree, power dissipation of 0.18 mW, and the trans-conductance variation over the common-mode input range of only about 2.45%.
出处
《电子技术应用》
北大核心
2012年第11期48-50,54,共4页
Application of Electronic Technique
关键词
运算放大器
低压
恒跨导
轨对轨
operational amplifier
low voltage
constant trans-conductance
Rail-to-Rail
