Title :
A temperature-stable CMOS variable-gain amplifier with 80-dB linearly controlled gain range
Author :
Yamaji, Takafumi ; Kanou, Nobuo ; Itakura, Tetsuro
Author_Institution :
Corporate Res. & Dev. Center, Toshiba Corp., Kawasaki, Japan
fDate :
5/1/2002 12:00:00 AM
Abstract :
A CMOS variable-gain amplifier (VGA) using subthreshold exponential region transistors with master-slave control technique is proposed. The proposed technique is applied to an intermediate-frequency VGA with a quadrature demodulator for wireless receivers. The test chip is fabricated using a 0.25-μm CMOS technology. An 80-dB linearly controlled gain range is achieved with exponential voltage-to-current converters using MOS transistors biased in a subthreshold exponential region, and the master-slave control circuits make the gain-control characteristic insensitive to the temperature. The experimental results indicate that the proposed technique is effective for a CMOS variable-gain amplifier
Keywords :
CMOS analogue integrated circuits; circuit stability; feedback amplifiers; gain control; intermediate-frequency amplifiers; radio receivers; 0.25 micron; 80 dB; CMOS VGA; CMOS variable-gain amplifier; IF amplifier; exponential voltage-to-current converters; gain-control characteristic; intermediate-frequency amplifier; linearly controlled gain range; master-slave control technique; quadrature demodulator; subthreshold exponential region transistors; temperature-stable amplifier; wireless receivers; CMOS technology; Circuit testing; Communication system control; Demodulation; MOSFETs; Multiaccess communication; Temperature control; Temperature dependence; Temperature sensors; Voltage control;
Journal_Title :
Solid-State Circuits, IEEE Journal of
