Power Integrity Measurement

Power integrity has been growing in importance in digital designs for quite some time.  Many designs now require special simulation tools to help make design trade offs for decoupling capacitors, power and ground plane assignments, and return path management.  If you think you're at the point of needing these design tools, I think it is first important to figure out how to effectively measure and quantify power integrity problems.  There are plenty of references explaining how to perform and set up simulations, but the details about the measurement end are sometimes pretty hard to find.  There was recently a discussion in the SI mailing list on this issue where a few references were pointed out [1] [2] [3].  These provide some good practical information on making power integrity measurements, although they still gloss over some of the important details such as test fixture setup and measurement interpretation.

[1] Alexander, Mark. February 28, 2005. "Power Distribution System Design (PDS): Using Bypass/Decoupling Capacitors." XAPP623 from Xilinx Corporation. [Internet, WWW, PDF]. Available: Available in .PDF format; Addresss: http://www.xilinx.com/support/documentation/application_notes/xapp623.pdf. [Accessed October 14, 2008].

[2] Altera Corporation. February 2004. "Guidelines for Designing High-Speed FPGA PCBs." AN315 from Altera Corporation [Internet, WWW, PDF]. Available: Available in .PDF format; Address: http://www.altera.com/literature/an/an315.pdf. [Accessed October 14, 2008].

[3] Agilent Corporation. September 5, 2008. "Tips and Techniques for Making Power Supply Noise Measurements with an Oscilloscope." Application Note 1592 from Agilent Corporation. [Internet, WWW, PDF]. Available: Available in .PDF format; Address: http://cp.literature.agilent.com/litweb/pdf/5989-6755EN.pdf. [Accessed October 14, 2008].