A 83-GHz and 68-dBΩ TIA with 2.3 pA/√ Hz: Towards High Speed and Low Noise Optical Receivers

This paper presents a fully differential and linear TIA design. Various trade off opportunities available in shunt-feedback TIAs are discussed and a design is proposed to reduce the input-referred noise without compromising its bandwidth. The design has been simulated in a 90 nm BiCMOS process from Global Foundries (GF-9HP) and offers an efficient area-noise tradeoff. The proposed approach is compared with a conventional post-amplifier-based equalization methodology. Results suggest that the proposed approach can reduce the noise by allowing a bigger value of first stage transimpedance gain without any significant deterioration of bandwidth. The proposed design achieves a BW of 83 GHz with an average input-referred noise density of 2.32 pA/√Hz. All simulations include the effect of photodiode modeled as a current source with 65 fF capacitance. As per the author's best knowledge, the proposed design has the lowest input-referred noise and highest value of feedback resistance (R f ) for an overall BW of 83 GHz. This TIA is aimed to support data streams beyond 100 Gb/s.