半导体学报2011，Vol.32Issue(2)：85-90,6.DOI:10.1088/1674-4926/32/2/025003
A baseband LPF for GSM, TD-SCDMA and WCDMA multi-mode transmitters*
A baseband LPF for GSM, TD-SCDMA and WCDMA multi-mode transmitters*
摘要
Abstract
This paper describes a low-pass reconfigurable baseband filter for GSM, TD-SCDMA and WCDMA multi-mode transmitters. To comply with 3GPP emission mask and limit TX leakage at the RX band, the outof-band noise performance is optimized. Due to the distortion caused by the subthreshold leakage current of the switches used in capacitor array, a capacitor bypass technique is proposed to improve the filter's linearity. An automatic frequency tuning circuit is adopted to compensate the cut-off frequency variation. Simulation results show that the filter achieves an in-band input-referred third-order intercept point (IIP3) of 47 dBm at 1.2-V power supply and the out-of-band noise can meet TX SAW-less requirement for WCDMA & TD-SCDMA. The baseband filter incorporates -40 to 0 dB programmable gain control that is accurately variable in 0.5 dB steps. The filter's cut-off frequency can be reconfigured for GSM/TD-SCDMA/WCDMA multi-mode transmitter. The implemented baseband filter draws 3.6 mA from a 1.2-V supply in a 0.13μm CMOS process.关键词
active-RC filter/ multi-mode transmitter/ analog baseband/ tuning circuitKey words
active-RC filter/ multi-mode transmitter/ analog baseband/ tuning circuit引用本文复制引用
Yu Yongchang,Han Kefeng,Wang Lifang,Tan Xi,Min Hao..A baseband LPF for GSM, TD-SCDMA and WCDMA multi-mode transmitters*[J].半导体学报,2011,32(2):85-90,6.基金项目
Project supported by the Important National Science & Technology Specific Projects (No.2009ZX01031-003-002) and the National High Technology Research and Development Program of China (No.2009AA011605). （No.2009ZX01031-003-002）
