Eye diagram estimation of 8B/10B encoded high-speed serial link for signal integrity test using silicone rubber socket

In this paper, an eye diagram of the 8B/10B encoded signal is estimated by using the single bit response (SBR) of a silicone rubber socket. The 8B/10B encoding scheme has been used in the HDMI. Because the eye diagram heavily depends on the bit patterns, the encoded PRBS patterns should be considered when the resultant eye diagram is obtained. Likewise, the 8B/10B encoding scheme must also considered when the eye diagram is estimated. An eye diagram estimation method finds the worst contour of the eye diagram using partial information. This can be done in significantly reduced testing time by using a SBR, as opposed to all of PRBS patterns. In high-speed IC tests, the ICs are interconnected with an automated test environment (ATE) by test sockets. Since the resultant eye diagram consists of 8B/10B encoded signal, the eye diagram should be estimated considering the encoding scheme. This paper considers the mapping scheme of Lattice RD 1012. In conclusion, the eye diagram of the 8B/10B encoded signal by Lattice RD 1012 is estimated using the SBR of the silicone rubber socket under the various compression effect. The estimated eye diagram and simulated eye diagram of the encoded PBRS patterns are nearly identical. Therefore, the proposed eye diagram estimation including the conventional 8B/10B encoding scheme is verified by comparing with that of PRBS patterns.