Hardware interview practice
Place isolation and retention correctly
A switchable producer domain drives an always-on consumer. Some producer state must survive power-off, and producer outputs are invalid while its supply is off. Which low-power structures are required?
Choose one
Answer choices
- A. Retention flops for the state that must survive, plus isolation on signals leaving the switchable domain before or while its supply turns off.
- B. Isolation alone, because clamping outputs automatically saves and restores all internal sequential state.
- C. Only clock gating, because stopping the clock removes leakage and preserves state through complete power removal.
- D. Retention flops alone, because retained internal state guarantees every powered-off output remains electrically valid.