Transimpedance amplifier

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In electronics, a transimpedance amplifier (TIA) is a current to voltage converter, almost exclusively implemented with one or more operational amplifiers (opamps). The TIA can be used to amplify the current output of Geiger–Müller tubes, photo multiplier tubes, accelerometers, photodetectors and other sensors (that are modeled well as a current source) into a usable voltage. Current to voltage converters are used with sensors that have a current response to their measured physical quantity that is more linear than their voltage response. This is the case with photodiodes where it is not uncommon for the current response to have better than 1% nonlinearity over a wide range of light input. The transimpedance amplifier presents a low impedance to the sensor and isolates it from the output voltage of the operational amplifier. In its simplest form (Fig. 1), a transimpedance amplifier is just an opamp with a large-valued feedback resistor, Rf. This resistor sets the amplifier's transimpedance...

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