Package Size Calculator

IPC-2221 is the generic standard for PCB design, containing conservative charts for internal/external conductors. IPC-2152 is the newer, more accurate standard based on extensive empirical data. It accounts for copper thickness, board material, and thermal environment more precisely. For new designs, IPC-2152 is recommended as it can lead to more optimal (often smaller) trace widths.

The calculations provide highly accurate estimates based on industry-standard physics models. Key factors influencing real-world results include:

• Manufacturing tolerances: Actual etched copper width and thickness can vary.
• Board environment: Nearby traces, planes, and airflow significantly affect thermal performance.
• Material consistency: Dielectric constant (Dk) and loss tangent can vary between laminate batches.

Always apply appropriate safety factors and consult your PCB manufacturer's capabilities.

The tool seamlessly converts between units. The choice depends on your workflow:

• Millimeters (mm): Used in most modern metric-based designs and fabrication files (Gerber).
• Mils (thousandths of an inch): Traditional unit in PCB design; common in North America and for specifying trace/space rules.
• Inches: Typically used for overall board dimensions.

Recommendation: Use mils for trace/space rules and mm for board outlines and mechanical features. The tool's unit converter provides instant conversions.

This setting significantly impacts current capacity and temperature rise.

• External Layers (Top/Bottom): Traces can dissipate heat to the ambient air on one side. They generally have higher current capacity for the same width and temperature rise.
• Internal Layers: Traces are embedded within the laminate, dissipating heat primarily through conduction to adjacent layers. They have lower current capacity and typically require wider traces for the same current.

Always specify the correct layer in the calculator. Power traces are often placed on external layers if space allows.

At high frequencies (typically above ~10 MHz for standard designs), current crowds towards the surface of the conductor (skin effect), increasing effective resistance.

• The Impedance Calculator tab accounts for frequency-dependent losses when you enter a signal frequency.
• For power traces with high-frequency AC components, effective cross-sectional area decreases, which may require wider traces than DC calculations suggest.
• Use the Frequency field in the Trace Parameters tab to see adjusted recommendations for AC current.

The safety factor derates the maximum current to account for uncertainties.

• 1.0x (No Derating): Use only for well-controlled prototyping with known materials and environment.
• 1.5x - 2.0x (Typical): Recommended for most commercial and industrial products. This is the tool's default.
• 3.0x or higher (Conservative): Used for high-reliability applications (aerospace, medical, automotive), or when manufacturing tolerances are poor.

The chosen factor is applied to your input current before calculating the required trace width.