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ADC-Based Backplane Receivers: Motivations, Issues and Future

  • Chung, Hayun (Department of Electronics and Information Engineering, Korea University)
  • Received : 2015.09.25
  • Accepted : 2015.12.28
  • Published : 2016.06.30

Abstract

The analog-to-digital-converter-based (ADC-based) backplane receivers that consist of a front-end ADC followed by a digital equalizer are gaining more popularity in recent years, as they support more sophisticated equalization required for high data rates, scale better with fabrication technology, and are more immune to PVT variations. Unfortunately, designing an ADC-based receiver that meets tight power and performance budgets of high-speed backplane link systems is non-trivial as both front-end ADC and digital equalizer can be power consuming and complex when running at high speed. This paper reviews the state of art designs for the front-end ADC and digital equalizers to suggest implementation choices that can achieve high speed while maintaining low power consumption and complexity. Design-space exploration using system-level models of the ADC-based receiver allows through analysis on the impact of design parameters, providing useful information in optimizing the power and performance of the receiver at the early stage of design. The system-level simulation results with newer device parameters reveal that, although the power consumption of the ADC-based receiver may not comparable to the receivers with analog equalizers yet, they will become more attractive as the fabrication technology continues to scale as power consumption of digital equalizer scales well with process.

Keywords

References

  1. Harwood, M. et al: A 12.5Gb/s SerDes in 65nm CMOS using a baud- rate ADC with digital receiver equalization and clock recovery. IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 436-437 (2007)
  2. Cao, J. et al.: A 500mW digitally calibrated AFE in 65nm CMOS for 10Gb/s serial links over backplane and multimode fiber. IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 370-371 (2009)
  3. Chen, E.-H. et al.: 10Gb/s serial I/O receiver based on variable reference ADC. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 288-289 (2011)
  4. Kim, J. et al.: Equalizer design and performance trade-offs in ADC-based serial links. IEEE Trans. Circuits Syst. I, 58(8), 2096-2107 (2011) https://doi.org/10.1109/TCSI.2011.2162465
  5. Chen, E.-H., Yousry, R., Yang, C.-K.: Power optimized ADC-based serial link receiver. IEEE J. Solid-State Circuits, 47(4), 938-951 (2012) https://doi.org/10.1109/JSSC.2012.2185356
  6. Ting, C. et al.: A blind baud-rate ADC-based CDR. IEEE J. Solid-State Circuits, 48(12), 3285-3295 (2013) https://doi.org/10.1109/JSSC.2013.2279023
  7. Zhang, B. et al.: A 195mW/55mW dual-path receiver AFE for multistandard 8.5-to-11.5 Gb/s serial links in 40nm CMOS. IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 34-35 (2013)
  8. Shafik, A. et al.: A 10Gb/s hybrid ADC-based receiver with embedded 3-tap analog FFE and dynamically-enabled digital equalization in 65nm CMOS. IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 62-63 (2015)
  9. Choi, M. et al.: A 6-bit 5-GSample/s Nyquist A/D converter in 65nm CMOS. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 16-17 (2008)
  10. Park, S., Palaskas, Y., Flynn, M.: A 4-GS/s 4-bit Flash ADC in $0.18-{\mu}m$ CMOS. IEEE J. Solid-State Circuits, 42(9), 1865-1872 (2007) https://doi.org/10.1109/JSSC.2007.903053
  11. Chen, E.-H. et al.: Adaptation of CDR and full scale range of ADC-based Serdes receiver. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 12-13 (2009)
  12. Chen, V.-C., Pileggi, L.: An 8.5mW 5GS/s 6b flash ADC with dynamic offset calibration in 32nm CMOS SOI. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 264-265 (2013)
  13. El-Chammas, M., Murmann, B.: A 12-GS/s 81-mW 5-bit time-interleaved flash ADC with background timing skew calibration. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 157-158 (2010)
  14. Nazemi, A. et al.: A 10.3GS/s 6bit (5.1 ENOB at Nyquist) time-interleaved/pipelined ADC using open-loop amplifiers and digital calibration in 90nm CMOS. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 18-19 (2008)
  15. Verma, S. et al.: A 10.3GS/s 6b flash ADC for 10G Ethernet applications. IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 462-463 (2013)
  16. Tabasy, E. et al.: A 6b 10GS/s TI-SAR ADC with embedded 2-tap FFE/1-tap DFE in 65nm CMOS. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 260-261 (2013)
  17. Kull, L. et al.: A 35mW 8b 8.8GS/s SAR ADC with low-power capacitive reference buffers in 32nm Digital SOI CMOS. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 264-265 (2013)
  18. Peters, W.: IEEE p802.3ap task force channel model material. http://www.ieee802.org/3/ap/public/channel_model (2006). Accessed 14 July 2015
  19. Murmann, B.: ADC performance survey 1997-2014 (ISSCC & VLSI symposium). http://web.stanford.edu/murmann/adcsurvey.html (2014). Accessed 07 March 2015
  20. Yang, C.-K., Chen, E.-H.: ADC-based serial I/O receivers. Proc. IEEE Custom Integrated Circuits Conf., 323-330 (2009)
  21. Chung, H. et al.: A 7.5 GS/s flash ADC and a 10.24 GS/s time-interleaved ADC for backplane receivers in 65 nm CMOS. Analog Integrated Circuits and Signal Processing, 85(2), 299-310 (2015) https://doi.org/10.1007/s10470-015-0624-x
  22. Tual, S.L. et al.: A 20GHz-BW 6b 10GS/s 32mW time-interleaved SAR ADC with master T&H in 28nm UTBB FDSOI technology. IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 382-383 (2014)
  23. Chung, H. et al.: A 7.5-GS/s 3.8-ENOB 52-mW flash ADC with clock duty cycle control in 65nm CMOS. IEEE Symp. VLSI Circuits Dig. Tech. Papers, 268-269 (2009)
  24. Chung, H., Wei, G.-Y.: ADC-based backplane receiver design-space exploration. IEEE Trans. VLSI Syst., 22(7), 1539-1547 (2014) https://doi.org/10.1109/TVLSI.2013.2275742
  25. Kasturia, S., Winters, H.: Techniques for highspeed implementation of nonlinear cancellation. IEEE J. Sel. Areas Commun., 9(5) 711-717 (1991) https://doi.org/10.1109/49.87640
  26. Varzaghani, A., Yang, C.-K.: A 4.8 GS/s 5-bit ADC-based receiver with embedded DFE for signal equalization. IEEE J. Solid-State Circuits, 44(3), 901-915 (2009) https://doi.org/10.1109/JSSC.2009.2013765