Power Distribution Network Design Tool
The easy-to-use power distribution network (PDN) design tool is a graphical tool used with all Altera® FPGAs to optimize the board-level PDN. The purpose of the board-level PDN is to distribute power and return currents from the voltage regulating module (VRM) to the FPGA power supplies, and support optimal transceiver signal integrity and FPGA performance. Figure 1 shows the different components of the PDN.
Figure 1. Model of the Power Distribution Network
View Full Size
For each power supply, you must choose a network of bulk and ceramic decoupling capacitors. While you can use SPICE simulation to simulate the circuit, the PDN design tool provides a fast, accurate and interactive way to determine the right number of decoupling capacitors for optimal cost and performance trade-offs. By determining the optimal set of decoupling capacitors for a given design, you can save board space and board layout is made easier.
You can select the number and values of the capacitors in the spreadsheet (see Figure 2) and the tool calculates the composite impedance of the PDN along with the impedance characteristics of the VRM, the decoupling capacitors and their mounting inductance, the PCB, and the FPGA with on-package and on-chip capacitors.
Figure 2. Spreadsheet Entry for PDN Optimization
View Full Size
Optimal performance is achieved if the composite impedance meets the target impedance (see Figure 3). The target impedance is derived from FPGA power requirements. Altera's Quartus® II development software PowerPlay power analysis technology allows you to accurately analyze the FPGA's power consumption for each power rail.
Figure 3. Impedance Results after PDN Optimization
View Full Size
The PDN design and optimization process is described in detail in the High-Speed Board Design Advisor Power Distribution Network technical brief (PDF) of Altera's High-Speed Board Design Advisor. The advisor provides tested and proven guidelines and the best design practices for key aspects of your high-speed board design.
Design with confidence using Altera’s tools and board design guidelines and get your design right the first time with the right performance and cost trade-offs.
Download a copy of the PDN tool and the user-guide now!
|
Literature
> 
