Design techniques for 32.75Gb/s and 56Gb/s wireline transceivers in 16nm FinFET

Abstract

This paper describes circuit techniques for high speed transceivers used in FPGA applications. Three architectures in 16nm FinFET encompassing NRZ and PAM4 modulation are discussed. First, a 0.5–32.75Gb/s flexible reach NRZ transceiver achieves BER <10−15 over 30dB loss backplane at 32.75Gb/s while consuming 577mW. It features 3 stages of CTLE including a gain segmented AGC, 15 tap DFE, 2 LC PLLs and a ring PLL to offer continuous frequency range over both long and short reach channels. Secondly, a 40–56Gb/s PAM4 receiver with analog front end achieves BER<10−10 over a 10dB loss channel at 56Gb/s with crosstalk and consumes 230mW. It uses a direct feedback 10-tap DFE for power efficiency. Lastly, a 40–56Gb/s ADC based PAM4 transceiver achieves BER<10−8 over a 31dB loss channel at 56Gb/s with crosstalk. It features a 4 stage CTLE, an 8-bit SAR ADC, a 14 tap FFE and a 1 tap DFE to achieve long reach operation.