Simulated Transimpedance Amplifier Performance Analysis through Channel Length Modification for Fiber Optics Applications

Abstract: A proposed transimpedance amplifier was simulated using channel length modification. The amplifier consists of a feedforward input stage followed by a common gate-common source (CG-CS) configuration. A series of channel lengths (45, 90, and 130 nm) in complementary metal-oxide semiconductor (CMOS) technology was implemented for comparative performance analysis within the same proposed topology. There are two key advantages of this study. First, the trade-off between gain and bandwidth, as well as the input-referred noise current, remains applicable when the channel length is increased from 45, 90, and 130 nm. Second, power consumption decreases as the channel length increases for the same topology. The total power consumption series (0.621, 0.29, and 0.175 mW) corresponds to the above channel length series. Corresponding bandwidths of (1.69, 1.35, and 1.10 GHz) were reported, with respective transimpedance amplifier (TIA) gains of (44.78, 46.39, and 47.94 dBΩ). The input-referred noise current was reduced to (15.24, 10.77, and 9.40 pA⁄√(H_z )) for the channel lengths of 45, 90, and 130 nm, respectively, aligning with the trends observed in bandwidth and TIA gain. Keywords: Transimpedance amplifier, Feedforward, Front-end preamplifier, RGC. PACS: 85.40.-e, 07.50.Ek, 84.30.-r.