In vacuum, or in a potted assembly, you should use the internal layer guidelines even for the external layers.ġc. Since the Trace Width Calculator tries to control the temperature rise of the traces, it makes the internal traces wider. A good heat insulator blankets the internal layers, so they get hotter for a given width and current. ANSWER: In air, the external layers have better heat transfer due to convection. Intuitively I would say the required internal trace width would be less than the external case since the external trace can peal off the opposite is true according to the calculator? Why?ġb. QUESTION: I used your PCB trace width calculator. The formulas used here will simply extrapolate when the values are outside of these ranges.ġb.
ANSWER: The original graphs that this tool is based on (published in IPC-D-275) only cover up to 35 Amps, up to 0.4 inches of trace width, from 10 to 100 degrees C of temperature rise, and copper of 0.5 to 3 ounces per square foot. I entered a 65 amp current requirement and it returned a track width that must be incorrect.ġa. QUESTION: Very cool PCB width tool! I would like to know its limits though.
Posted in : Calculators, Electrical Engineering, PCBĬomments 1.Where k, b, and c are constants resulting from curve fitting to the IPC-2221įor geometry diagrams, click on the pictures below.įor frequently asked questions, see the comments. The trace width is calculated as follows:Īrea = (Current/(k*(Temp_Rise)^b))^(1/c) Units and other settings are saved between sessions This Javascript web calculator calculates the trace width for printed circuitīoards based on a curve fit to IPC-2221 (formerly IPC-D-275). PCB Trace Width Calculator January 31, 2006
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