A DC-43.5 GHz CMOS Switched-Type Attenuator with Capacitive Compensation Technique

This paper presents an ultra-broadband 5-bit switched-type attenuator (STA). The resistor values of the five attenuation cells are optimized to ensure accurate amplitude tuning. Capacitive compensation technique is adopted to reduce phase error and enhance the bandwidth. Fabricated in 65-nm CMOS technology, the 5-bit STA occupies a core chip area of 0.036 mm(2). It exhibits ultra-broadband (i.e., DC to 43.5 GHz) operation with 15.5-dB amplitude tuning range and 0.5-dB tuning step. The insertion loss of the reference state is 1.5 5.3 dB from DC to 43.5 GHz. The RMS amplitude error and phase error are < 0.19 dB and < 3.1 degrees over the whole measured band.