HIGH LINEARITY CMOS VARIABLE GAIN AMPLIFIER FOR UWB APPLICATIONS

A large dynamic-range Variable Gain Amplifier (VGA) suitable for Ultra Wide Band (UWB) applications is presented. The VGA is composed of three programmable variable gain amplifier stages followed by an output buffer. Such wide bandwidth allows our proposed VGA to be used in multi-standard protocols. Power reduction is developed for the variable gain amplifier stages. Thorough analyses of the mid-band gain and noise are presented; and design tradeoffs are carefully handled. The VGA circuit is designed and simulated in 0.13 μm IBM-CMOS process; the overall VGA with buffer consumes 25 mA from a 1.5 V supply. The VGA achieves 54.5 dB dynamic-range (DR), 17.6 dBm IIP3, -42.31 dB THD at peak-to-peak differential output voltage of 1 V, and frequency 400 MHz. Moreover; the proposed circuit reports a good noise performance; the average integrated noise is 121.6 nV/Hz at minimum gain of -0.5 dB.