CMOS LIMITING OPTICAL PREAMPLIFIERS USING DYNAMIC BIASING FOR WIDE DYNAMIC RANGE

This paper presents limiting techniques for improving the dynamic range of CMOS optical preamplifiers while minimizing power dissipation. A fully-differential transimpedance amplifier using diodes clamps to limit output voltage is analyzed. A design with a transimpedance gain of 5k � and total bias current of 2.9mA is simulated handle a maximum photocurrent of 400µA at 100Mbps, with an input-referred noise of 177nA(rms). Dynamic biasing techniques are then introduced to improve dynamic range. A Class A topology is simulated to double maximum photocurrent at similar power, gain, speed and noise parameters, while a Class AB topology is shown to handle a maximum photocurrent of 1.5mA. 1

CMOS LIMITING OPTICAL PREAMPLIFIERS USING DYNAMIC BIASING FOR WIDE DYNAMIC RANGE

This paper presents limiting techniques for improving the dynamic range of CMOS optical preamplifiers while minimizing power dissipation. A fully-differential transimpedance amplifier using diodes clamps to limit output voltage is analyzed. A design with a transimpedance gain of 5k � and total bias current of 2.9mA is simulated handle a maximum photocurrent of 400µA at 100Mbps, with an input-referred noise of 177nA(rms). Dynamic biasing techniques are then introduced to improve dynamic range. A Class A topology is simulated to double maximum photocurrent at similar power, gain, speed and noise parameters, while a Class AB topology is shown to handle a maximum photocurrent of 1.5mA. 1