12-Gb/s over four balanced lines utilizing NRZ braid clock signaling with no data overhead and spread transition scheme for 8K UHD intra-panel interfaces

This paper presents a new pin/energy-efficient data and clock signaling scheme, named braid clock signaling (BCS). This signaling scheme efficiently embeds clock information into the data stream without data overhead, unnecessary pins, and channels for clock. To remove the data overhead, the clock information is embedded in every other data period. This high transition density (TD) leads to the enhanced jitter tracking performance of a receiver and increased stability. Furthermore, a spread transition scheme (STS) removes the additional power consumption for the embedded clock with little electromagnetic interference (EMI). As non-return-to-zero (NRZ) signaling uses only two voltage levels, the NRZ BCS secures a large input voltage margin at the receiver side, unlike other pin-efficient multi-level signaling schemes. An analysis of the secured voltage margin shows improved energy efficiency over conventional pin-efficient multi-level signaling schemes, even without consideration of their clocking power dissipation. The prototype transceiver is fabricated in a 28-nm CMOS process with a 12-Gb/s delay-locked loop (DLL)-based receiver over four lines.