The graph shows the temperature rise on the copper traces, not the temperature of the traces.
The temperature shown in the graph needs to be added to the expected ambient temperature the board will exist at.
The data is for a single trace passing a certain amount of current, which might be acceptable for a two-sided card.
However a number of stacked layers each with there own high current traces might generate a hot spot on the board.
The graph above shows the amount of current an External trace on a
printed wiring board can handle.
The picture provides the current rating
based on trace cross section in square mils, temperature rise and current in amperes.
The first graph shows the rise in temperature of a trace as the current through the trace is increased, up to 35 amps.
In addition the graph also indicates a temperature rise from 10 degrees Centigrade [room temperature] up to 100C for a trace width up to 700 mils.
For example; if the trace width is 100 square mils, that trace can accept
between 3.5A and 10 amps depending on the acceptable temperature rise.
The bottom graph shows the weight of the copper vs. conductor width and cross section of the conductor trace.
Key Phrase:
How much current will a trace handle
What is the current rating of a trace
What trace width will handle a certain amount of current.
Internal
Trace Capacity, Buried traces on an internal layer of the board
Dictionary of PCB Terms; Technical jargon used with circuit boards.
PWB Production Vendors, Companies producing Printed Circuit Boards
The table provides minimum conductor spacing vs. voltage
Voltage Between Conductors | ||
Surface Layers | Internal Layers | |
0.005" | 0.004" | |
0.015" | 0.008" | |
0.030" | 0.010" |
Related Military Standards;
MIL-PRF-38535E - Integrated Circuits (Microcircuits)
Manufacturing
MIL-PRF-31032 - Printed Circuit Board/Printed Wiring Board,
General Specification for
MIL-PRF-55110F - Printed Wiring Board, Rigid, General
Specification for
MIL-C-46058C - Insulating Compound, Electrical (For Coating
Printed Circuit Assemblies)
MIL-C-47175A(MI) - Compound, Polyurethane, for Conformal Coating
of Electronic Circuitry
MIL-C-14550B - Copper Plating, (Electro-Deposited)
MIL-I-46058C - Insulating Compound, Electrical (for Coating
Printed Circuit Assemblies)
MIL-STD-275E - Printed Wiring for Electronic Equipment
MIL-STD-2118 - Flexible and Rigid-Flex Printed Wiring for
Electronic Equipment Design Requirements for
MIL-T-10727C - Tin Plating: Electro-Deposited or Hot-Dipped, for
Ferrous and Non-ferrous metals
RoHS - Restriction of Hazardous Substances
When required, in large the trace to take advantage of the copper thermal conductivity.
Graphic of Minimum
Annular Ring, What is a Minimum Annular Ring.
Graph of PWB
Ground Potential, moving away from a single point ground connection
[example].
.... Description
of Ground Loops
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