Title :
A 4th-order active-gm-RC reconfigurable filter with time constant auto-tuning
Author :
Liu Junbo ; Fan Xiangning ; Bao Kuan
Author_Institution :
Inst. of RF - & OE-ICs, Southeast Univ., Nanjing, China
Abstract :
Based on TSMC 0.18μm RF CMOS process, a 4th-order Butterworth low-pass filter (LPF) used in a multi-mode and multi-standard wireless receiver (for WCDMA and GPS/Galileo) is presented in this paper. The LPF adopts active-gm-RC structure, and can satisfy both WCDMA and GPS/Galileo bandwidth requirements, which maximizes hardware reuse. In order to improve the accuracy of the bandwidth, a RC time constant auto-tuning circuit is applied. The layout of the LPF with auto-tuning circuit occupies a 900μm×870μm area. With 1.8V power supply, the core circuit of the LPF consumes 1mW and 1.6 mW for WCDMA and GPS/Galileo respectively. The out of band attenuation rate is -80dB/10 octave and the bandwidth error of each mode is less than 4%.
Keywords :
Butterworth filters; CMOS integrated circuits; Global Positioning System; RC circuits; circuit tuning; code division multiple access; low-pass filters; radio receivers; radiofrequency integrated circuits; 4th-order Butterworth low-pass filter; 4th-order active-gm-RC reconfigurable filter; GPS/Galileo; LPF layout; RC time constant auto-tuning circuit; TSMC RF CMOS process; WCDMA; bandwidth accuracy; bandwidth error; bandwidth requirement; hardware reuse; multimode wireless receiver; multistandard wireless receiver; out-of-band attenuation rate; power 1 mW; power 1.6 mW; size 0.18 mum; voltage 1.8 V; Capacitors; Filtering theory; Global Positioning System; Low pass filters; Multiaccess communication; Spread spectrum communication; Tuning;
Conference_Titel :
High Speed Intelligent Communication Forum (HSIC), 2012 4th International
Conference_Location :
Nanjing, Jiangsu
Print_ISBN :
978-1-4673-0678-2
Electronic_ISBN :
978-1-4673-0676-8
DOI :
10.1109/HSIC.2012.6213024
