Steve Sandler Answers Your PDN Questions (Power Electronics’ Q&A Series)
Power Electronics received a question about why PDN is measured using a VNA and not an oscilloscope. We asked our expert, Steve Sandler to weigh in on the subject.
QUESTION: If PDN is an assessment of the voltage to a CPU then why is it measured using a VNA and not an oscilloscope?
ANSWER: First, your understanding of PDN is perfectly correct. The PDN includes the voltage regulator, printed circuit board traces or planes, via’s and decoupling capacitors including the capacitor series resistance (ESR) and inductance (ESL). The voltage arrives at the load (CPU) and must be within allowable limits. Internal to the CPU the bond wires and die capacitance also form part of the PDN.