Title :
A High Dynamic Range CMOS Variable Gain Amplifier for Mobile DTV Tuner
Author :
Xiao, Jianhong ; Mehr, Iuri ; Silva-Martinez, Jose
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas A&M Univ., College Station, TX
Abstract :
A high dynamic range RF variable gain amplifier (RFVGA) suitable for mobile digital television (DTV) tuners is presented. Variable gain is achieved using a capacitive attenuator and current-steering transconductance (Gm) stages, which provide high linearity with relatively low power consumption. A novel broadband input impedance matching scheme based on resistive shunt-feedback is proposed. This scheme allows the RFVGA to achieve a low noise figure. A gain control technique suitable for CMOS current-steering variable gain amplifiers is described; it features 1 dB per step resolution, independent of process and temperature variations. The chip is fabricated in six-metal 0.18mum CMOS technology and consumes 12.2mA current from 1.8V supply. The RFVGA achieves 16dB maximum gain, 33dB gain control range, a 4.3dB noise figure, and an IIP3 higher than 25dBm
Keywords :
CMOS analogue integrated circuits; circuit feedback; digital television; gain control; impedance matching; radiofrequency amplifiers; tuning; 0.18 micron; 1.8 V; 12.2 mA; 4.3 dB; RF variable gain amplifier; broadband amplifier; broadband input impedance matching; capacitive attenuator; current-steering transconductance stages; dynamic range CMOS variable gain amplifier; gain control; mobile digital television tuners; resistive shunt-feedback; Attenuators; Broadband amplifiers; CMOS technology; Digital TV; Dynamic range; Gain control; Noise figure; Radio frequency; Radiofrequency amplifiers; Tuners; Broadband amplifier; CMOS amplifier; current steering; input impedance matching; mobile TV; tuner; variable-gain amplifier;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2006.889386
