An Analysis on the Effectiveness of 2 and 3 Terminal Capacitors in PDN Design

While 3-terminal capacitors have been widely used in PDN design (attributed to their low ESL), the effectiveness of 3-terminal capacitors has not been fully verified. As they are more expensive than regular 2-terminal capacitors, it is important to understand their effectiveness. This presentation will explain an accurate characterization method to extract ESL of decoupling capacitors and why the ESL values listed in the data sheet are meaningless.  Based on the characterization results, the possibility/effectiveness of replacing 3-terminal capacitors with 2-terminal capacitors (which can greatly reduce cost) is discussed and experimentally validated.