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Method for a low cost impedance matching technique for reducing power and ground planes resonance

IP.com Disclosure Number: IPCOM000008238D
Publication Date: 2002-May-29
Document File: 4 page(s) / 61K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a low cost impedance matching technique for reducing power and ground planes resonance. Benefits include improved signal quality.

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Method for a low cost impedance matching technique for reducing power and ground planes resonance

Disclosed is a method for a low cost impedance matching technique for reducing power and ground planes resonance. Benefits include improved signal quality.

Background

              The power delivery network (PDN) is very susceptible to noise voltages at resonant frequencies, that is, frequencies at which standing waves occur between the planes. At resonant frequencies, devices connected to the PDN are affected by impedance from the power and ground connections and voltage spikes when the circuits are being driven with fast current edges. For example, with a resonant frequency of approximately 1.7 GHz, the peak value of the impedance is about 180 Ohm (see Figure 1).

              This problem is conventionally solved by adding resistors and decoupling capacitors to the circuit. Adding components substantially increases the cost of the product.

General description

      The disclosed method is the etching of long tail-like traces around the outer power plane to match the power and ground impedance, reducing the resonance between power and ground planes.

Advantages

      The disclosed method provides advantages, including:

·        Reduced impedance

·        Prevention of resonant frequencies and power spikes

·        Low-cost solution

·        Improved signal quality

Detailed description

              The disclosed method decreases the impedance at resonant frequencies between the power and ground planes by etching a few long tail-like traces at the outer side...