Low-cost AlGaAs/GaAs HBT multi-gigabit limiting amplifier packaged with a new plastic air tight cavity encapsulation process

A multigigabit limiting amplifier integrated circuit (IC) for optical transmission system was implemented with AlGaAs HBT technology and packaged in a plastic-molded-bottom-ground air-cavity package using an alpha-staged thermally setting epoxy which comes in a gel in an uncured state. The amplifier was designed to support differential input and output. Small signal performance of the packaged IC achieves 31 dB gain and f_{3 dB} of 4.6 GHz. A single output has 1.0 V_p-p swing with more than 32 dB dynamic range up to 5 Gb/s. The measured bit error rate applying to APD optical receiver at 2.5 Gb/s bit rate is -33.5 dBm at 1×10^-10 BER with 2²³-1 long 2.5 Gb/s NRZ PRBS pattern. The present packaging method was verified by subjecting it to the industry standard condition “c” gross leak test and the overall yield of the air cavity encapsulation process is more than 99%. This method is readily capable of mass production using automated equipment