Implementing a receiver in a fast data transfer system - A feasibility study

Abstract This report is an outcome of a master degree project at Linköpings University in cooperation with Micronic Laser Systems AB. The purpose with this master degree project was to investigate how to implement a receiver in a data transfer system. The system consists of several data channels, where every channel consists of three parts: driver, transmission lines and receiver. The driver sends low amplitude differential signals via the transmission lines to the receiver that amplifies and converts it to a single-ended signal. The receiver has to be fast and be able to feed an output signal with high voltage swing. It is also needed for the receiver to have low power consumption since they are close to the load, which is sensitive to heat. Different amplifier architectures were investigated to find a suitable circuit for the given prerequisites. In this report the advantages and disadvantages of voltage and current feedback are discussed. The conclusions of this work are that in a system with an amplifier as a receiver with differential transmission lines, a single operational amplifier cannot be used. An input stage is needed to isolate the feedback net from the inputs of the operational amplifier. When fast rise time and large output swing are wanted the best amplifier architecture is current feedback amplifiers. A current feedback amplifier in CMOS with the required high voltages and slew rate is hard to realize without very high power consumption.This report is an outcome of a master degree project at Linköpings University in cooperation with Micronic Laser Systems AB. The purpose with this master degree project was to investigate how to implement a receiver in a data transfer system. The system consists of several data channels, where every channel consists of three parts: driver, transmission lines and receiver. The driver sends low amplitude differential signals via the transmission lines to the receiver that amplifies and converts it to a single-ended signal. The receiver has to be fast and be able to feed an output signal with high voltage swing. It is also needed for the receiver to have low power consumption since they are close to the load, which is sensitive to heat. Different amplifier architectures were investigated to find a suitable circuit for the given prerequisites. In this report the advantages and disadvantages of voltage and current feedback are discussed. The conclusions of this work are that in a system with an amplifier as a receiver with differential transmission lines, a single operational amplifier cannot be used. An input stage is needed to isolate the feedback net from the inputs of the operational amplifier. When fast rise time and large output swing are wanted the best amplifier architecture is current feedback amplifiers. A current feedback amplifier in CMOS with the required high voltages and slew rate is hard to realize without very high power consumption.