应用于30GHz锁相环的高性能电荷泵设计

Design of High Performance Charge Pump for 30GHz Phase Locked Loop

基于IBM 0.13μm CMOS工艺,设计了一款应用于30GHz低杂散锁相环的电荷泵电路。该电荷泵采用带隙基准为电流源和运算放大器提供偏置,采用复制支路和比较器实现上下电流源的静态匹配,将输入输出轨对轨运算放大器接成单位增益缓冲器来避免电荷共享效应,通过加入互补开关管来减小时钟馈通和电荷注入效应。后仿真结果表明,在电源电压为2.5V,电荷泵电流为200μA,调谐范围为0.5～2V时,充放电电流的最大静态失配小于0.1%;在750kHz环路带宽下,计算得到锁相环参考杂散小于-72dBc,满足IEEE 802.15.3c标准对60GHz本振信号杂散的要求。

A charge pump used in 30 GHz low spurs phase locked loop （PLI.） was designed based on the IBM 0. 13 μm CMOS process. A bandgap was used to bias the charge pump current sources and operational amplifier. A replica branch and a comparator were employed to match the charging and discharging currents. A unity gain buffer which was implemented by a rail-to-rail operational amplifier was used to avoid charge sharing. The effects of clock feed through and charge injection were reduced by adding the complementary switching transistors. The post simulation results showed that the maximum quiescent current mismatch was less than 0. 1 ~ while the tuning voltage was ranged from 0.5 V to 2 V, and the charge pump current was 200 /~A from 2.5 V power supply. The calculated reference spurs of the PLL was less than 72 dBc while the closed loop bandwidth was 750 kHz, meeting the IEEE 802.15.3c standard requirements of spurs for the LO signal of 60 GHz.