A 15-Gb/s preamplifier with 10-dB gain control and 8-mV sensitivity in 65-nm CMOS

A broadband preamplifier with gain control and automated common-mode level regulation is presented. It is implemented in 65-nm CMOS as part of an analog front-end (AFE) that is especially suitable for wireline receivers incorporating digital signal processing or multilevel modulation. S-parameter measurements of the receiver show that the preamplifier remains well matched to the channel impedance across all gain settings with an S₁₁ of less than -8 dB to frequencies beyond 25 GHz. The measured S₂₁ of the receiver shows that the preamplifier is capable of achieving 10 dB of gain control. The preamplifier alone consumes from 16.7 mA to 56.7 mA from a 1.2 V supply, depending on its gain setting.