In the realm of digital design, signal integrity has become a critical issue, and is posing increasing challenges to the design engineers. Many signal integrity problems are electromagnetic phenomena in nature and hence related to the EMI/EMC.
The term Signal Integrity (SI) addresses two concerns in the electrical design aspects, the timing and the quality of the signal. Does the signal reach its destination when it is supposed to? And also, when it gets there, is it in good condition? The goal of signal integrity analysis is to ensure reliable high-speed data transmission. In a digital system, a signal is transmitted from one component to another in the form of logic 1 or 0, which is actually at certain reference voltage levels. At the input gate of a receiver, voltage above the reference value Vih is considered as logic high, while voltage below the reference value Vil is considered as logic low. Any delay of the data or distortion of the data waveform will result in a failure of the data transmission.
However, as speed increases,high-frequency effects take over and even the shortest lines can suffer from problems such as ringing, crosstalk,reflections, and ground bounce, seriously hampering the integrity (response) of the signal. You can overcome these issues by following good design techniques and simple layout guidelines of signal integrity.