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A CMOS infrared wireless optical receiver front-end is presented. A stable variable-gain fully-differential transimpedance feedback amplifier is designed employing a current-mode amplifier as the feedforward gain element. More than a triple variation of the transimpedance gain, from 0.3 kΩ to 1 kΩ, the variable-gain transimpedance amplifier achieves desirable gain-bandwidth independence. For an infrared wireless optical receiver front-end employing the transimpedance amplifier, the optical preamplifier achieves a transimpedance gain of 66 dBΩ and a bandwidth of 114 MHz with a 5 pF photodiode capacitance, and a power consumption of 17.4 mW.