Title :
A Switchable-Order Gm-C Baseband Filter With Wide Digital Tuning for Configurable Radio Receivers
Author :
Chamla, David ; Kaiser, Andreas ; Cathelin, Andreia ; Belot, Didier
Author_Institution :
STMicroelectron., Crolles
fDate :
7/1/2007 12:00:00 AM
Abstract :
A master/slave technique which allows digital tuning of a Gm-C filter´s cut-off frequency is proposed. It relies on an accurate transconductance division technique, fixing the reference frequency independently from the filter cut-off frequency. The design of a digitally-tunable Gm-C switchable third/fifth- order Butterworth low-pass filter in a 0.13-mum 1.2-V CMOS process is also proposed. An extended tuning range (above 25:1) is obtained through the design of a linear very widely tunable transconductor. Measured results prove this chip to be compatible with the baseband part of direct-conversion cellular receivers, from GSM to W-CDMA, with a tuning accuracy better than 5% over the entire tuning range.
Keywords :
Butterworth filters; CMOS digital integrated circuits; cellular radio; circuit tuning; code division multiple access; continuous time filters; digital filters; low-pass filters; radio receivers; switched filters; Butterworth low-pass filter; CMOS process; GSM; W-CDMA; baseband continuous-time filter; direct-conversion cellular receivers; filter cut-off frequency; master-slave technique; multimode radio receivers; on-chip automatic tuning; size 0.13 mum; switchable-order Gm-C baseband filter; transconductance division technique; tunable triode linear transconductor; voltage 1.2 V; wide digital tuning; CMOS process; Cutoff frequency; Digital filters; Frequency conversion; Low pass filters; Master-slave; Semiconductor device measurement; Transconductance; Transconductors; Tuning; Baseband continuous-time filter; configurable G$_{m}$-C filter; multimode radio receivers; on-chip automatic tuning; tunable triode linear transconductor;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2007.899125
