Circuit design for a 15-Gb/s Si bipolar decision circuit

The authors have designed and fabricated a high-bit-rate and high-input-sensitivity decision circuit using an advanced super-self-aligned Si bipolar process technology by 0.5-μm photolithography. To realize both a very high bit rate and a high input sensitivity at the same time required not only advanced device technology but also a sophisticated circuit design to extract the maximum performance from the device. The circuit design included optimization of individual transistor sizes to boost the speed and adoption of a wideband preamplifier to enhance the sensitivity. The circuit operates at up to 15 Gb/s with an input sensitivity of 40 mV_p-p