A Study of ESD-mmWave-Switch Co-Design of 28GHz Distributed Travelling Wave Switch in 22nm FDSOI for 5G Systems

Abstract

This paper presents the first co-design analysis of 28GHz broadband single-pole double-throw (SPDT) distributed travelling wave RF switches implemented in a foundry 22nm fully-depleted silicon-on-insulator (FDSOI) CMOS technology, featuring 9KV full-chip human body model (HBM) electrostatic discharge (ESD) protection. This ESD-protected millimeter wave (mmWave) SPDT switch is designed for highly reliable above-6GHz 5th-generation (5G) mobile systems, covering the n257 and n258 bands. Adverse influences of the inherent ESD-induced parasitic effects are characterized, revealing that the ESD effects can severely affect RF switch performance in mmWave bands. A new ESD-mmWave-switch co-design technique was developed to address this ESD design challenge for mmWave switches, which was validated in Si measurements, e.g., improving the switch insertion loss (IL) by ∼ 4 dB for the 28GHz SPDT travelling wave switches fabricated. This design also achieves the highest reported charged device model (CDM) ESD protection of ∼ 1.84 A in Si testing. This study proves that ESD-mmWave-switch co-design is critical to RF front-end designs for 5G mobile systems, which typically require robust ESD protection, but are also very sensitive to the inevitable ESD-induced parasitic effects.