A GaAs-HBT broadband amplifier with near-f/sub T/ cut-off frequency for high-bitrate transmission

broadband amplifier for high-bilrate lransmission is presenfed, using a standard CaAs-HBTprocess wifh fr and fnw of 36 ond 170 GHz, respective@, af the operating bias point The design fakes opfimum advantage of the available fechnoloe, reaching 75% of fr, a record value for GaAs HBT Well-opened outpuf eye diagrams at 20 and 40 Cbps are obtained wifh 1.4 Vpp and 1.2 Vpp, respectively, as well as a 4 Vpp output swing at 20 Gbps for 1.7 Vpp input signal. The measured eye diagrams demonstrafe the potential for applications as 40 Cbps pre-amplifier and 20 Cbps modulator drivers