Low Phase Variation CMOS Digital Attenuator

摘要

A low phase variation attenuator uses a combined attenuation path and a phase network to significantly reduce a phase error between a reference signal and an attenuated signal without degrading the insertion loss. A grounded parallel connection of a resistor and a capacitor is employed in series with an attenuation transistor, which is connected to a middle of a two resistor voltage divider. The two resistor voltage divider includes two resistors of equal resistance that are connected in a series connection. The two resistor voltage divider is connected in a parallel connection with a reference transistor, which functions as a main switch for the transmission or attenuation of a radio frequency (RF) signal.