BeginnerQuestion 6 of 40Source PDF page 14

How does temperature affect leakage power?

From PDVerse Low-Power Physical Design Mentor Guide · pdVerse Mentor Guide

Definition

Leakage power is temperature-dependent — this dependence is well characterized in device data, and it is exactly why the industry-standard worst-case power signoff corner is defined at maximum operating temperature, alongside fast process and maximum voltage.

Mentor Explanation

The important point for a beginner is that temperature isn't just a timing concern (via so-called temperature inversion, where slow-process delays can actually worsen at lower temperatures) — it's independently baked into how power signoff corners are chosen. Since the power signoff corner deliberately pushes temperature to its maximum, that corner choice itself tells you leakage is treated as getting worse, not better, as temperature rises.

Example

When a designer runs power signoff, they don't use room-temperature numbers — they intentionally evaluate at the maximum specified junction temperature precisely because that is where leakage-driven power is worst.

Why It Matters

Ignoring temperature effects on leakage could cause a design to pass power estimates in a lab bench-top test but fail once it is running hot inside a real system enclosure.

Common Beginner Mistake

A beginner mistake is assuming a single 'typical' temperature is good enough for power estimation, when the whole point of corner-based signoff is to guarantee correctness across the full temperature range, using the maximum-temperature corner for power. Figure 1.1 — A single power domain, sharing one primary supply and one ground across all its logic POWERDOMAINPD_TOP Core Logic VDD VSS Sequential Logic

Visual explanationLow-power context: How does temperature affect leakage power?
Low-power context: How does temperature affect leakage power?A three-step concept map summarizes the focus, core answer, and practical verification for How does temperature affect leakage power?Question focusHow does temperatureaffect leakage power?Core answerLeakage power istemperature-dependent —this dependence is wellcharacterized in device…Verify in practiceCheck domain supplies,strategies, mappedcells, and legal powerstates.Understand → explain the mechanism → verify the assumptions

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