A transimpedance amplifier (TIA) converts an input current into a proportional voltage, typically using an inverting op-amp with a feedback resistor (Rf). It's also a common building block that helps explain the performance and stability limits of many other op-amp circuits. Despite or because of their simple topologies, TIAs pose rigid tradeoffs among their gain, noise, and bandwidth (BW). In this article, we design a TIA in 28-nm CMOS technology while targeting the. The current-to-voltage amplifier can be described as having a gain, because the output amplitude is equal to the input amplitude multiplied by a number chosen by the designer, but it's a different type of gain because the output signal and the input signal have different units and therefore cannot.
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