Perspective of Low-Power and High-Speed Wireless Inter-Chip Communications for SiP Integration

Performance gap between computation in a chip and communication between chips is widening. "System in a package" (SiP) reduces chip distance significantly, enabling a high-speed and low-power interface. Electrical non-contact interfaces using inductive/capacitive coupling have advantages over mechanical interfaces employing through silicon vias (TSV) and micro bumps. In this paper, a perspective of using wireless links between stacked chips in a package is presented. Techniques for high-speed and low-power data communications are discussed in various levels from signaling, circuit design, IC layout, and magnetic field design, as well as cross talk analysis and its countermeasures. A 1 Tb/s 3W transceiver in 0.18mum CMOS is presented. Both clock and data are transmitted by inductive coupling. 1024 data transceivers are arranged with a pitch of 30mum. A 4-phases time division multiple access (TDMA) technique reduces crosstalk effectively. Measured bit error rate (BER) is lower than 10^-13. Bi-phase modulation (BPM) is employed to improve noise immunity, resulting in power reduction