A fully-differential, flipped-voltage-follower-based (FVF) transimpedance design for optical receivers with large-area photodetectors

Abstract

This article presents a transimpedance amplifier (TIA) design suitable for 1 Gbps operation using a 4-level pulse amplitude modulation scheme. It is aimed toward communication protocols with large-area photodetectors, such as plastic-optical-fiber, visible light communications, and biomedical applications. The TIA leverages a flipped-voltage-follower as well as global current feedback to extend the bandwidth of the TIA and operates up to 400 MHz with a very low static power while driving a very large capacitance. The TIA has a static power consumption of only 1.2 mW at a 1 V supply voltage. Additionally, the fully-differential version of the proposed TIA is introduced in the case of using spatially-modulated light detectors. The design is validated with post-layout simulations employing a commercially available 40 nm CMOS process. Mismatch and corner simulations demonstrate that the proposed TIA can still provide the specifications in the worst-case scenarios.