A Flip-Chip, Co-Packaged With Photodiode, High-speed TIA in 16nm FinFET CMOS


A technical paper titled “A 112-Gb/s —8.2-dBm Sensitivity 4-PAM Linear TIA in 16-nm CMOS With Co-Packaged Photodiodes” was published by researchers at University of Toronto, Alphawave IP, and Huawei Technologies Canada.


“A flip-chip co-packaged linear transimpedance amplifier (TIA) in 16-nm fin field effect transistor (FinFET) CMOS demonstrating 112-Gb/s four-level pulse-amplitude modulation (4-PAM) with −8.2-dBm sensitivity is presented in support for optical receivers required in the next-generation intra-data center links. A proposed three-stage TIA is comprised of a shunt-feedback stage followed by digitally programmable continuous-time linear equalizers (CTLEs) and a variable gain amplifier (VGA). Broadband low-noise design is achieved by having the first stage with much lower bandwidth (BW) followed by the proposed BW recovering CTLEs. A low-power design is supported by the inverter-based single-ended architecture with a single-ended-to-pseudo-differential conversion in the last stage. TIA’s BW extension is further supported by optimizing the photodiode-to-receiver (PD-to-RX) interconnect and utilizing several inductive peaking techniques. It achieves 63-dB Ω gain, 32-GHz BW, and an average input-referred current noise density of 16.9 pA/ Hz−−−√ while operating at 0.9-V supply and consuming 47-mW power. Opto-electrical measurements are performed on a co-packaged prototype comprised of identical proposed TIAs in CMOS with combinations of various commercial PDs and PD-to-RX interconnect lengths confirming 112-Gb/s 4-PAM reception meeting pre-forward error correction (FEC) symbol error rate (SER) of 4.8×104 without any post-equalization.”

Find the technical paper here. March 2023.

Dhruv Patel, Alireza Sharif-Bakhtiar, Tony Chan Carusone, “A 112-Gb/s —8.2-dBm Sensitivity 4-PAM Linear TIA in 16-nm CMOS With Co-Packaged Photodiodes”, IEEE Journal of Solid-State Circuits, vol.58, no.3, pp.771-784, 2023.

Related Reading
Complementary metal-oxide semiconductor (CMOS) Knowledge Center
Fin field-effect transistor (FinFET) Knowledge Center

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