Paul D. Franzon

AC Coupled Interconnect


AC Coupled Interconnect (ACCI) is a novel contactless, high bandwidth, low-power packaging structures and circuits for chip packaging, sockets, connectors and 3D ICs. High-speed digital system-level interconnect does not require DC connections to transmit data. AC connections (series capacitors or transformers) can be used instead. The advantages of doing this include:

  • High density. We can acheve a 60 um pitch for chip-to-package connections and a 250 um pitch for socket and conenctor connections. The size advantage comes about due to the inherently compliant nature of an interconnect not requiring a metal to metal join.
  • High Bandwidth. We have demonstrated the concept from DC to over 6 Gbps on serial links. It is scalable beyond 20 Gbps per wire.
  • Low power. The scheme requires less than 1/3rd the power per Gbps of conventional I/O.
  • Low Noise (good signal integrity). We achieve low ISI without using DSP and have demonstrated low Bit Error Rates and acceptable crosstalk and simultaneous swtiching noise (SSN).
  • Simultaneous Power and Data. Power and data can be transmitted simultaneously in a contactless connector. We have demonstrated this advantage in a new headphone format.

This work is supported by AFRL, SRC, NSF and DARPA.

Sample Images:

(left to right : 0.18 um flip chip experimental die; 6 Gbps eye diagram at RX output.)





Overview Presentation #1 (focused on high density packaging and principles)

Overview Presentation #2 (focused on connectors)

Selected Publications:

  • Wenxu Zhao; Gadfort, P.; Erickson, E.; Franzon, P.D., "A compact inductively coupled connector for mobile devices," Electronic Components and Technology Conference (ECTC), 2013 IEEE 63rd , vol., no., pp.2385,2390, 28-31 May 2013 paper
  • Su, B.; Pitts, W.S.; Franzon, P.D.; Wilson, J., "A zero power consumption Multi-Capacitor structure for voltage summing in high-speed FFE," Electrical Performance of Electronic Packaging and Systems (EPEPS), 2010 IEEE 19th Conference on , vol., no., pp.13,16, 25-27 Oct. 2010 paper
  • Franzon, Paul; Wilson, John; Li, Ming, "Thermal isolation in 3D chip stacks using vacuum gaps and capacitive or inductive communications," 3D Systems Integration Conference (3DIC), 2010 IEEE International , vol., no., pp.1,4, 16-18 Nov. 2010
  • Lei Luo; Wilson, J.; Mick, S.; Jian Xu; Liang Zhang; Erickson, E.; Franzon, P., "A 36Gb/s ACCI Multi-Channel Bus using a Fully Differential Pulse Receiver," Custom Integrated Circuits Conference, 2006. CICC '06. IEEE , vol., no., pp.773,776, 10-13 Sept. 2006
  • Wilson, J.M.; Mick, S.E.; Xu, J.; Luo, L.; Erickson, E.L.; Franzon, P.D., "Considerations for Transmission Line Design on MCMs using AC Coupled Interconnect with Buried Solder Bumps," Signal Propagation on Interconnects, 2006. IEEE Workshop on, vol., no., pp.281,282, 9-12 May 2006
  • J. Xu, J. Wilson, S. Mick, L. Luo and P. Franzon, “2.8 Gb/s Inductively Coupled Interconnect for 3-D ICs,” in Japan VLSI Symposium, June, 2005. paper, presentation
  • K. Chandrasakar, Z. Feng, J. Wilson, S. Mick, P. Franzon, “Inductively Coupled Board-to-Board Connectors,” in Proc. ECTC 2005, May 2005. paper, presentation
  • L. Luo, J. M. Wilson, S.E. Mick, J. Xu, L. Zhang, and P.D. Franzon, “A 3 Gb/s AC Coupled Chip-to-Chip Communication,” 2005 International Solid State Circuits Conference, San Francisco, Feb. 2005. paper, presentation
  • S. Mick, L. Luo, J. Wilson, P. Franzon, “Buried Bump and AC Coupled Interconnection Technology, IEEE Trans. Adv.Packaging, 27(1), Feb, 2004, pp. 121-125. paper
  • J. Xu, L. Luo, S. Mick, J. Wilson, P. Franzon, “AC Coupled Interconnect for Dense 3-Ds," in IEEE Transactions on Nuclear Science (TNS), VOl 5(15), Oct, 2004, pp. 2156-2160.
  • Paul Franzon, Angus Kingon, Stephen Mick, John Wilson, Lei Luo, Karthik Chandrasakhar, Jian Xu, Salvatore Bonafede , Alan Huffman, Chad Statler, Richard LaBennett, Invited Paper , “High Frequency, High Density Interconnect Using AC Coupling,” Fall MRS Conference, Boston MA, December 2003.
  • Paul Franzon, Stephen Mick, John Wilson, Lei Luo, Karthik Chandrasakhar, Invited Paper, “AC Coupled Interconnect for High-Density High-Bandwidth Packaging” Proc. SPIE, Microlectronics: Design, Technology and Packaging, Perth , Australia , December 2003. pp 67-69.
  • Paul Franzon, Stephen Mick, John Wilson, Lei Luo, Karthik Chandrasakhar, Invited Paper, “AC Coupled Interconnect for High-Density High-Bandwidth Packaging,” Japan SSDM, Tokyo , Japan , September, 2003.
  • Jian Xu, Stephen Mick, John Wilson, Lei Luo, Karthik Chandrasakhar, Paul Franzon, “AC Coupled Interconnect for Dense 3-D Systems”, Proc. IEEE Conference on Nuclear Science and Imaging, Seattle Washington, October 2003.
  • S. Mick, L. Luo, J. Wilson, P. Franzon, “Buried solder bump connections for high-density capacitive coupling,” IEEE Electrical Performance of Electronic Packaging, 2002, pp. 205-208.
  • S.E. Mick, L. Luo, J.M. Wilson, P.D. Franzon, “Buried Solder Bump Connections for High-Density Capacitive Coupling,” IEEE Electrical Performance on Electornic Packaging, October, 2002.
  • S. E. Mick, J. M. Wilson, and P. Franzon, “4 Gbps AC Coupled Interconnection,” ( invited paper ), IEEE Custom Integrated Circuits Conference, May 12-16, 2002, pp. 133-140.



Last Modified: May 2016