A 0.18- $\mu{\hbox {m}}$ CMOS 1.25-Gbps Automatic-Gain-Control Amplifier

A 1.25-Gbps automatic-gain-control (AGC) amplifier is presented and it has been fabricated in 0.18-mum CMOS technology. To achieve a constant settling time, this AGC amplifier with the proposed variable gain amplifier (VGA) is presented. The measured VGA has a gain tuning range of 28.5 dB from -10 to 18.5 dB, and its measured group delay is about 12.15 ns. For the bit-error rate of 10^-12, the sensitivity and the overload for this AGC amplifier are 25 and 430 mV, respectively. It achieves input dynamic range of 24.7 dB. The power dissipation is 43.2 mW from a single 1.8-V supply voltage. The chip area is 0.82 mm times 0.56 mm includes I/O pads.