Hold on there

What this hold-time violation question tests

This is a medium-difficulty question on digital design and static timing analysis (STA). It assesses whether you understand the physical and logical causes of hold-time failures in synchronous circuits — a critical concern in chip design and physical implementation.

Hold-time violations occur when data at a flip-flop input changes too soon after the clock edge, violating the minimum time the input must remain stable. To answer this question well, you need to reason about clock skew, interconnect delays, logic-path delays, and how they interact to create (or prevent) violations. The question rewards not just familiarity with the term, but understanding the root mechanisms and how different design choices — placement, routing, buffer insertion, clock distribution — contribute to or mitigate the problem.

• Setup and hold time constraints
• Clock skew and its effect on timing margins
• Combinational logic delays on data paths
• Buffer and inverter insertion in clock trees