High-Speed Signaling: Jitter Modeling, Analysis, and Budgeting

Chapter 13. SSN Reduction Codes and Signaling

Dan Oh

As discussed in the previous chapter, simultaneous switching noise (SSN) is one of the major bottlenecks facing single-ended signaling interfaces. SSN is caused by current change over the inductance of a power distribution network (PDN). Because the PDN’s inductance is mainly due to the package’s parasitic inductance, SSN is conventionally reduced by increasing the package ball or pin counts (see Figure 12.2, in Chapter 12, “SSN Modeling and Simulation,” for the pin-count trend in graphics memory systems). However, increasing the pin count has limited effectiveness, because inductance decays slowly as the number of pins increases, causing physical design improvements to be difficult and expensive. ...