PDNs

PDN stands for Power Delivery Network, a term used in electronics to describe the network that delivers regulated electrical power from a source to the load, typically an integrated circuit or a board. The PDN includes the power supply, decoupling and bulk capacitors, voltage regulators, power planes, traces, vias, and on-chip PMU. Its primary function is to maintain a stable supply voltage at the load during steady operation and under transient current demands, minimizing voltage droop and switching noise that can affect performance.

Design and architecture emphasize impedance control across frequency. Lower impedance at the switching frequencies reduces voltage fluctuations. Designers place bulk and decoupling capacitors close to load pins, create low-impedance power and ground planes, and minimize loop inductance with short, wide traces and well-placed vias. Separation of analog and digital rails and careful return-path management are common practices.

Analysis and testing: PDN impedance budgets specify allowable impedance versus frequency. Tools include circuit-level SPICE models and electromagnetic simulations; time-domain and frequency-domain analyses. Measurements use network analyzers or impedance spectroscopy to verify compliance.

Applications: PDNs are essential in CPUs, GPUs, memory, mobile systems-on-chip, FPGAs, and other high-speed digital systems. In practice, PDN robustness affects voltage regulation, timing, thermal behavior, and electromagnetic emissions.

Variations: while the term PDN is most often used for on-board distribution, it may also refer to power delivery networks within integrated circuits, where on-die power grids and voltage regulators handle local delivery from the core supply.