A 0.18 μm CMOS transimpedance amplifier with 26 dB dynamic range at 2.5 Gb/s

A new transimpedance amplifier (TIA) for 2.5 Gb/s optical communications fabricated in a standard 0.18 μm CMOS process is presented. The proposed TIA is based on a conventional structure with an inverting voltage amplifier and a feedback resistor, but incorporates a new technique to enhance the input dynamic range and to prevent the TIA from saturation at high input currents. According to electrical characterization the receiver shows an optical sensitivity of −26 dB m for a BER=10−12, assuming a responsivity of 1 A/W, and an optical power dynamic range above 26 dB. The power consumption of the core is only 10.6 mW at a single supply voltage of 1.8 V.

Research highlights
► A 1.8-V 0.18-μm CMOS transimpedance amplifier targeting 2.5 Gb/s is presented.
► A good noise performance is achieved, leading to an optical sensitivity of −26 dBm.
► The proposed TIA incorporates a new technique to enhance the input dynamic range.
► It shows an optical power dynamic range above 26 dB without duty cycle distortion.
► Our proposal is also suitable for technologies with an even lower supply voltage.