Flip-flop timing parameters — identify the item that is NOT standard Which of the following is not generally recognized as a standard flip-flop timing parameter?

Introduction / Context:
Flip-flops are characterized by specific timing parameters that determine how they interact with clock and data signals. Correctly identifying these parameters is essential for reliable synchronous design and timing closure.

Given Data / Assumptions:

• Edge-triggered flip-flops in synchronous systems.
• Standard datasheet terminology.

Concept / Approach:
Common parameters include setup time (tsu), hold time (th), propagation delay or clock-to-Q time (tCQ), and sometimes recovery/removal times for asynchronous inputs. The term “interval time” is not a standard flip-flop timing specification and does not appear as a defined parameter in vendor datasheets.

Step-by-Step Reasoning:

Verification / Alternative check:
Reviewing any standard logic family datasheet (TTL/CMOS/FPGA primitives) shows no “interval time”; instead, they specify tsu, th, tpd, tCQ, tr/tf, and asynchronous timing specs.

Why Other Options Are Wrong:

• Hold time: minimum time D must remain stable after the clock edge.
• Propagation delay time / Clock-to-Q: time for output to respond to clock/data change.
• Setup time: minimum time D must be stable before the clock edge.
• Clock-to-Q time: a specific propagation delay metric from clock to output.

Common Pitfalls:

• Using nonstandard terms which can mask real timing violations in analysis.

Final Answer:
Interval time