A design of DC-2 GHz linear-controlled CMOS attenuator

Abstract

To reaffinn the use of a mainstream CMOS process for designing passive-like attenuator structures, a linear-controlled variable attenuator is realized with 0.35um CMOS process, which covers the broad frequency band (DC-I GHz). Compared to existing passive-like CMOS attenuators, it is demonstrated that this work advances the frequency band from MHz to GHz, and reduces the size. To elevate the limit of bandwidth, an alternative topology, which covers DC2GHz, is proposed as well. Operation principle and its characteristics are exolained in detail.

CMOS blocks for on-chip RF test

“…Unlike the previous work [11,12] we do not aim at continuously variable attenuation. For the loopback test discrete attenuation levels are sufficient.…”

“…This idea can be implemented in two ways, i.e. as a resistive network with transistor switches or as an all-MOS transistor circuit [11,12]. In the first case one can anticipate a good linearity whereas the alternative solution might be appealing for its lower area overhead.…”