Analysis and Design of Transimpedance Amplifiers for Optical Receivers

Preface

Transimpedance amplifiers (TIA) are used at the front end of optical receivers. They can also be found at the front end of read circuits for optical storage systems and laser RADAR systems for distance measurement. But TIAs are not limited only to optical applications; particle/radiation detector chips, vision sensor chips, biological sensor chips, motion sensors in microelectromechanical systems, and wideband radio receivers also make use of TIAs.

This broad range of applications is not surprising. The TIA is essentially a sensitive and fast current measurement device: A weak current signal, typically originating from a sensor such as a photodetector, a particle/radiation detector, a biological sensor electrode, a MEMS electrostatic transducer, or a radio receiver antenna, is amplified and converted into a voltage signal. The term transimpedance derives from the older term transfer impedance, which indicates that an input current at one port is producing an output voltage at another port.

The term transimpedance amplifier may evoke the image of a voltage amplifier with a shunt-feedback resistor. However, this is just one particular implementation. Several other topologies exist and novel TIA circuits are still being invented today. Each circuit presents a different trade-off between sensitivity (noise), speed (bandwidth), power, area, and other performance measures. With each application having its own set of requirements, different applications benefit from different ...