A 0-TO-40-GHZ DIRECT-COUPLED DISTRIBUTED BASEBAND AMPLIFIER IC WITH SCFL INTERFACE

We have developed a distributed baseband amplifier IC with a distribut ed source-coupled FET logic (SCFL) level transformer. The amplifier an d the SCFL level transformer are directly coupled by a distributed lev el-shift circuit. The amplifier incorporates our new loss-compensation circuit to improve high-frequency performance. The IC, which was fabr icated using commercially-available GaAs MESFET's, has a gain of 5dB a nd a 0-to-41-GHz bandwidth. It can also output a 40-Gbit/s pulse wavef orm on the SCFL logic circuit. This is the highest performance among a ll reported GaAs MESFET baseband amplifiers with an SCFL interface.