transimpedancevõimendiga

A transimpedance amplifier (TIA) is a current-to-voltage converter. It is an operational amplifier circuit configured to convert an input current into an output voltage. The input current flows through a feedback resistor, and the operational amplifier adjusts its output voltage to maintain the inverting input at virtual ground. This means the voltage at the inverting input is essentially zero, so the entire input current is forced to flow through the feedback resistor. The output voltage is then proportional to the input current and the value of the feedback resistor.

TIAs are commonly used to amplify the small currents produced by photodetectors such as photodiodes and photomultiplier tubes. These devices generate a current that is proportional to the incident light intensity. By converting this current to a voltage, the signal can be easily processed by subsequent analog or digital circuits. The transimpedance gain, which is the ratio of output voltage to input current, is determined by the feedback resistor value. A larger feedback resistor results in higher gain, meaning a small input current produces a larger output voltage.

The bandwidth of a TIA is a critical parameter and is typically limited by the capacitance at the inverting input (which includes the photodetector capacitance and amplifier input capacitance) and the feedback resistor. A common trade-off exists between gain and bandwidth; higher gain generally leads to lower bandwidth. Various circuit techniques, such as using a smaller feedback resistor and employing active compensation, can be used to improve the bandwidth while maintaining acceptable gain.