A critical component in phased-array ultrasound receivers is the variable-gain amplifier (VGA), sometimes referred to as a time-gain control (TGC) amplifier. In this application note, we examine how VGA output-referred noise and gain can have a pronounced affect on ultrasound pulsed Doppler dynamic range and sensitivity, and how the MAX2037 octal ultrasound VGA has optimized these parameters to yield the best overall system performance in a typical receiver lineup.