片上锁相环调谐的低功耗中频复数滤波器设计

Low-Power IF Complex Filter with on-Chip Tuning Circuit Based on PLL

讨论了应用于IEEE802.15.4标准低中频接收机的3阶贝塞尔复数gm-C滤波器,其中跨导器采用Nauta结构。为了消除工艺偏差、温度变化、老化对截止频率的影响,滤波器电路使用了片上锁相环调谐电路。滤波器设计采用HJTC-0.18μm1P6MCMOS混合工艺,中心频率为+3 MHz,-3 dB带宽为2.6 MHz。仿真结果显示临道、间道抑制分别为26.4、44 dB,镜像抑制为31.4 dB,带内SFDR为54.8 dB。复数滤波器电源电压为2.5 V,整体消耗的电流约为1.61 mA。

A 3rd order Bessel complex gm-C filter which uses Nauta＇s transconductor for a low-IF receiver of IEEE802.15.4 was discussed. To avoid variance of technology and enviorment effects on cut-off frequency this filter used an on-chip tuning circuit based on PLL. Based on HJTC-0.18 tsm 1P6M CMOS technology, the filter is centered at ＋ 3 MHz and have a passband of 2.6 MHz. Simulation results showed that adjacent and alternate channels are attenuated by 26.4 dB and 44 dB.The image signal is rejected by 31.4 dB and the in-band SFDR is 54.8 dB. The complex filter and tuning circuit dissipates 1.61 mA current from a 2.5 V supply.