An integrated 12 Gbps switch-mode driver MMIC with 5 VPP for digital transmitters in 100 nm GaN technology

A digital switch-mode amplifier MMIC integrating an differential amplifier and driver was realized in an 100 nm GaN technology with a transit frequency of 80 GHz. The circuit operates up to a bit rate of 12 Gbps while it was designed for a current-mode amplifier chain. Each of the two driver output channels delivers an adjustable output voltage swing of up to 5 V_PP. Due to the differential amplifier input stage with a very low minimum input voltage swing of 0.5 V_PP the MMIC allows a flexible operation used as limiting amplifier or digital pre-amplifier for a GaN final switch-mode stage. The high output power density of the GaN technology allows a further integration of the final switch-mode power amplifier stage which enables for the first time a fully integrated high power digital transmitter in GaN.