Most PCB designs start out with a correct and verified schematic in hand. The hard work of then converting the schematic design into a final PCB must then be undertaken. Quite often, even though the original design has been undertaken with care, the PCB version of the design will fail to work. Even if a schematic has been verified using a simulation, what the simulation of the design fails to account for is that the specifics of the PCB layout can insert unforeseen sources of error into a design implementation. This is especially true when it comes to using newer and higher speed components with their associated higher clock speeds in a design. Additionally, data transfer speeds between devices are also continually increasing and subject to the same types of error sources. These speed increases allow for small capacitance and inductance values inherent in PCB layouts to cause the PCB implementation of a design to fail.
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