Power Density Calculator
Work out power density instantly with clear inputs, formula shown and shareable results.
About Power Density Calculator
Average power density is power over die area, but hotspots concentrate several times that in small regions. Since thermal resistance is local, it is the hotspot density that determines peak junction temperature and therefore whether the part throttles.
Formula
Power density
average = P / A; hotspot = average x concentration ratio
Worked example
With the default values below, Power Density Calculator returns Average power density of 0.2969. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Chip power
- 95 W
- Die area
- 320 mm²
- Hotspot concentration
- 2.5 x
- Cooling capability
- 0.6 W/mm²
Results
- Average power density
- 0.2969 W/mm²
- Hotspot power density
- 0.7422 W/mm²
- Average density
- 29.69 W/cm²
- Cooling assessment
- Hotspot exceeds cooling capability - thermal throttling likely
Step by step
- 1Values used
- 2Power density
- 3Average power density= 0.2969 W/mm²
- 4Hotspot power density= 0.7422 W/mm²
- 5Average density= 29.69 W/cm²
- 6Cooling assessment= Hotspot exceeds cooling capability - thermal throttling likely
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why do hotspots matter more than average power?
Heat spreads only a few millimetres laterally in silicon, so a small high-power block can be tens of degrees hotter than the die average.
What densities are manageable?
Around 0.5-1 W/mm2 with a good heatsink, several W/mm2 with direct liquid cooling. Above that requires microfluidics or aggressive throttling.
Related Calculators
- Clock Tree Power Calculator
- Defect Density To Yield Calculator
- Dynamic Power Dissipation Calculator
- FPGA Power Estimate Calculator
- IR Drop In Power Grid Calculator
- Static Leakage Power Calculator
- Total Chip Power Calculator
- Transistor Density Calculator
- Amdahl Speedup Calculator
- ASIC Development Cost Calculator
You might also need
- Transistor Density CalculatorAlso in Semiconductor, VLSI & Hardware Design
- Clock Tree Power CalculatorAlso in Semiconductor, VLSI & Hardware Design
- Defect Density To Yield CalculatorAlso in Semiconductor, VLSI & Hardware Design
- Dynamic Power Dissipation CalculatorAlso in Semiconductor, VLSI & Hardware Design
- FPGA Power Estimate CalculatorAlso in Semiconductor, VLSI & Hardware Design
- IR Drop In Power Grid CalculatorAlso in Semiconductor, VLSI & Hardware Design