Signal integrity is the art of getting a signal from point A to point B with minimum distortion to that signal. The recent attention on this subject stems from the necessity to build systems with ever increasing throughput and from silicon manufacturing advances in geometry scaling that are causing system-level effects (such as crosstalk, transmission line effects, and voltage drops) to manifest themselves on the chip level in a detrimental way. The vast amount of literature on this subject almost exclusively references, and correctly so, high-speed signals that operate at a gigabit per second or higher. These signals are the most sensitive to these limitations and thus should receive the most attention. However, what the industry neglects is that the quality of these high-speed signals is highly dependent on the quality of the input reference clock that is used to generate these high-speed signals. The design of the clock network is equally deserving of attention on this subject of signal integrity.

Clock management in today's 10-Gbps systems cannot be left as the last design decision. Generating and distributing a 25-MHz TTL or LVTTL clock for systems with bit widths of 100ns or 10ns is a vastly different challenge than distributing a 161.13-MHz LVPECL or LVDS clock for a system with bit widths of 96ps. Clock management must be an early and integral part of the overall system design decision. It must be considered with the same technical depth as the data path and the elements on the data path. The buzz words used in clock management are the same buzz words used in data path design: low jitter, supply isolation, sharp edges, crosstalk, etc. Moving forward, the challenge for silicon manufacturers is how and what they will contribute to the system engineer’s toolbox to help solve or alleviate these problems in clock tree design. In this white paper, we will look at the innovations that IDT is bringing to the clock management market and the problems they specifically address.

Access the entire document on the Integrated Device Technology, Inc. (IDT) website.