Power Integrity Analysis: Important Considerations - Part 2

While designing a board, there are few important points to consider from the power integrity perspective:

• The primary aim of the designer is to provide clean power with lowest possible ripple and at the same time carry the desired current without too much of voltage drop
• The impedance of the power path must be below the target impedance. This ensures that loads receive the desired voltage from the power source
• The target impedance is not just at DC but up to a high frequencies starting from DC. The highest frequency to consider is the switching speed of the interfaces in the circuit
• Careful consideration to be given while designing the stack up and power plane must be in the close proximity of the ground plane
• Decoupling capacitors must be placed as close as possible to the IC. The trace connecting the capacitor to the IC pin must be thick to achieve low impedance
• Use tools like Hyperlynx to perform power integrity analysis which helps determine the DC drop, plane noise and impedance of the power distribution network (PDN)