Title :
A 90nm CMOS CT BPF for Bluetooth transceivers with DT 1b-switched-resistor cutoff-frequency control
Author :
Majima, Hideaki ; Hamada, Mototsugu
Author_Institution :
Toshiba, Kawasaki
Abstract :
In this paper, a scheme for tuning cutoff-frequency of filters is presented. Instead of using a multibit resistor bank, a 1b switched-resistor structure operating at 200 MHz is utilized. The effective RC time constant is controlled by the duty ratio of the 1b tuning pulse. DeltaSigma modulation with dithering mitigates the spurious effects. Compared to the conventional tuning scheme, finer cutoff frequency tuning and more linear control are achieved. The tuning scheme is applied to a channel-select filter in a Bluetooth transceiver resulting in 6.3 kHz-step cutoff -frequency control and less than 1.8 kHz of differential linearity. The transceiver is implemented in a 1.2 V 90 nm CMOS process.
Keywords :
Bluetooth; CMOS integrated circuits; RC circuits; band-pass filters; channel bank filters; circuit tuning; continuous time filters; delta-sigma modulation; switched filters; transceivers; Bluetooth transceiver; CMOS CT BPF; DT 1b-switched-resistor cutoff-frequency control; DeltaSigma modulation; channel-select filter; frequency 200 MHz; frequency tuning; linear control; multibit resistor bank; size 90 nm; voltage 1.2 V; Band pass filters; Bluetooth; CMOS process; Cutoff frequency; Delta modulation; Linearity; Radio control; Resistors; Transceivers; Tuning;
Conference_Titel :
Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009. IEEE International
Conference_Location :
San Francisco, CA
Print_ISBN :
978-1-4244-3458-9
DOI :
10.1109/ISSCC.2009.4977444
