Employing bias current feedback in MIC transimpedance amplifier to increase bandwidth

Abstract

SummaryThis paper presents an inductorless transimpedance amplifier (TIA) that employs bias feedback technique in a MOS‐based immittance converter (MIC) to achieve high bandwidth. The bias feedback technique is analyzed and explored as a supplementary approach to reduce the input impedance in a current buffer structure. Employing this technique in a MIC‐based TIA structure provides an additional degree of freedom for the design and helps reduce the trade‐off between bandwidth and power. The proposed structure is designed and simulated in 0.18 μm CMOS technology considering a 1 pF photodiode capacitance. The post‐layout simulation results show that the TIA provides a transimpedance gain of 50.9 dBΩ, a bandwidth of 6.1 GHz, and an input‐referred current noise of 9.9 pA/√Hz. The circuit consumes 3.42 mW from a 1.8 V supply and occupies 0.0046 μm2 area. Results are compared with TIAs reported in the literature, which confirms the effectiveness of the proposed modified MIC structure.