A PACKAGED BROAD-BAND MONOLITHIC VARIABLE GAIN AMPLIFIER IMPLEMENTED IN ALGAAS GAAS HBT TECHNOLOGY/

Broad-band amplifiers find application in fiber-optic communication li nk and instrumentation or serve as generic components in high-speed el ectronic test laboratories, With an advanced AlGaAs/GaAs heterojunctio n bipolar transistor (HBT) technology, we have designed and fabricated broad-band monolithic variable gain amplifiers (VGA's), High-speed pa ckages for the VGA's were carefully designed to minimize insertion and return losses and to suppress undesired package cavity resonances. Ac curate and efficient models for the packages were obtained based on ex perimental data so that their parasitic effects could be considered in the VGA design, The packaged VGA's provided 10-16 dB adjustable gain with approximately ii dB gain variations and constant group delay in t he DC-26 GHz band, and showed better than 10 dB input/output return lo sses in the amplifier passband, When the packaged VGA's were inserted in a 30 Gb/s electronic link, error-free operation was achieved for a 2(31) - 1 input pseudorandom bit sequence, These VGA's can be used in fiber-optic transmission systems with data rates up to 30 Gb/s.