Let%27s delve into how ASICs (Application-Specific Integrated Circuits) handle clock jitter and skew, both of which are critical for reliable and precise clock distribution:

1. Clock Skew:
- Definition: Clock skew refers to the variation in arrival times of clock signals at different parts of a chip.
- Causes: Process variations, temperature gradients, and wire delays introduce skew.
- Impact: Skew affects setup and hold times, potentially causing data errors.
- Mitigation Techniques:
- Clock Tree Synthesis: Optimal distribution of clock signals using buffers and repeaters.
- Delay-Locked Loops (DLLs): Align clock edges by adjusting delay elements.
- Phase-Locked Loops (PLLs): Synchronize clocks to a reference signal.
- Clock Skew Compensation: Dynamic adjustments based on real-time measurements.

2. Clock Jitter:
- Definition: Clock jitter is the variation in consecutive edges of the clock signal.
- Types:
- Cycle-to-cycle (short-term): Immediate variations between consecutive clock cycles.
- Long-term: Variation of the pulse width over time.
- Importance for Level-Sensitive Clocking: Jitter affects the effective cycle time.
- Mitigation Techniques:
- Low-Jitter Clock Sources: High-quality oscillators or crystal oscillators.
- Spread Spectrum Clocking (SSC): Intentional frequency modulation to reduce peak jitter.

3. Dealing with Clock Skew and Jitter:
- Clock Skew Reduction:
- Balance clock paths using H-tree or matched-tree structures.
- Route data and clock in opposite directions to eliminate races (at the cost of performance).
- Clock Jitter Handling:
- Use gated clocks to manage dynamic power consumption.
- Consider jitter in clock generation and distribution circuits.

In summary, ASICs employ clock synchronization techniques, minimize skew, and manage jitter to ensure reliable and precise clock distribution across the chip¹²⁵. ️<br>

(1) Lecture 9: Clocking, Clock Skew, Clock Jitter, Clock Distribution and .... https://users.ece.utexas.edu/~mcdermot/vlsi1/main/lectures/lecture_9.pdf.
(2) What is the difference between clock skew and clock jitter?. https://profound-tips.com/blog/what-is-the-difference-between-clock-skew-and-clock-jitter/.
(3) What is Clock Skew? Understanding Clock Skew in a Clock Distribution .... https://www.allaboutcircuits.com/technical-articles/what-is-clock-skew-understanding-clock-skew-and-clock-distribution-networks/.
(4) On-Chip Circuit for Measuring Period Jitter and Skew of Clock .... https://www.bioee.ee.columbia.edu/wp-content/uploads/2017/04/8.pdf.
(5) 时钟抖动(Jitter)和时钟偏斜(Skew) - 知乎 - 知乎专栏. https://zhuanlan.zhihu.com/p/449845451.

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