The article describes circuit schematics, features and design methodology of microwave integrated digital step attenuators (DSAs) based on SiGe technology (SiGe BiCMOS). The measured characteristics of the designed 0.1–4.5 GHz microwave monolithic integrated circuit (MMIC) DSA with a parallel and serial control driver are presented. The DSA bitness is 6 bit, attenuation range is 30 dB with a 1-dB step, and input power at the 1 dB gain compression is no less than 14 dBm. In addition to the wide bandwidth, advantages of the MMIC DSA are a good input and output matching, as well as low consumption current. The MMIC DSA can be used in microwave transmitters and receivers for different applications, including ones that are based on the systemon-a-chip concept.
