Edge-triggered flip-flop requirements: An edge-triggered flip-flop must have which of the following characteristics?

Introduction / Context:
Edge-triggered flip-flops capture data precisely at a transition of the clock. Understanding what they fundamentally require helps avoid misinterpretations of symbol details and clocking schemes.

Given Data / Assumptions:

• The device responds at an edge (rising or falling).
• We compare architectural requirements versus optional implementation details.
• Options include claims about special generators or extra inputs.

Concept / Approach:
An edge-triggered flip-flop needs internal circuitry that reacts quickly to the clock’s transition and briefly opens a sampling window. This implies fast internal response relative to the edge duration so metastability windows are minimized and multiple sampling within one pulse is avoided. It does not inherently require two separate inputs for rising and falling edges, nor does it mandate an external positive- or negative-transition pulse generator; those edges are provided by the system clock, and selection of edge polarity is a device attribute.

Step-by-Step Solution:

Verification / Alternative check:
Datasheets specify setup/hold and clock pulse characteristics, which reflect the device’s internal speed and edge-capture capability. No requirement exists for two separate inputs to handle both edge polarities.

Why Other Options Are Wrong:
At least two inputs: Edge polarity is inherent; devices select rising or falling edge via design, not dual inputs.

Positive-/negative-transition pulse generator: External generators are not mandatory; a clean clock edge suffices.

Common Pitfalls:
Confusing optional external pulse-shaping circuits with inherent device requirements. Misreading symbol bubbles and triangles as extra inputs.

Final Answer:
Very fast response times