A 2 GHz CMOS variable-gain amplifier with 50 dB linear-in-magnitude controlled gain range for 10GBase-LX4 Ethernet

Chia-Hsin Wu, Chang-Shun Liu, Shen-Luan Liu
2004 IEEE International Solid-State Circuits Conference (IEEE Cat. No.04CH37519)  
The standard of next-generation gigabit Ethernet, 10GBase-LX4 Ethernet, was finalized in 2003 and is emerging into network markets [1]. 10GBase-LX4 Ethernet employs wavelength division multiplexing (WDM) to carry different channels on different wavelengths on a bundled fiber. 8B/10B coding scheme is deployed to ensure transmission quality. Figure 26 .8.1 shows the sophisticated implementation of 10GBase-LX4 Ethernet system. Each channel carries 3.125Gb/s data after optical demultiplexing, and
more » ... multiplexing, and its own individual optical receiver circuits. This mandates a wideband variable gain amplifier (VGA) with wide controlled gain range. The VGA poses challenging constraints, such as bandwidth, tuning range, etc. The VGA reported here demonstrates a 2GHz bandwidth with 50dB linear-controlled gain range, which is the widest bandwidth reported in CMOS technology to date to the authors' knowledge.
doi:10.1109/isscc.2004.1332805 fatcat:kiyr6b4orjboblhwklwbqkw4jy