Showing papers by "Hyungsoo Kim published in 2004"

Suppression of GHz range power/ground inductive impedance and simultaneous switching noise using embedded film capacitors in multilayer packages and PCBs

Abstract: We measured and demonstrated the great advantages of embedded film capacitors in reducing power/ground inductive impedance and the suppression of SSN at frequencies up to 3 GHz for high-performance multilayer packages and PCBs. Eight-layer test PCBs were fabricated, and their inductive power/ground network impedances were measured as a function of film thickness, via distribution, and combined use with discrete decoupling capacitors, using a two-port self-impedance measurement method. This successfully demonstrated that the power/ground inductive impedance was reduced from 270 pH to 106 pH simply by using an embedded film capacitor instead of 16 discrete decoupling capacitors.

Epoxy/BaTiO/sub 3/ composite films and pastes for high dielectric constant and low-tolerance embedded capacitors fabrication in organic substrates

Abstract: Epoxy/BaTiO/sub 3/ composite embedded capacitor films (ECFs) were newly designed for high dielectric constant and low-tolerance (less than /spl plusmn/5%) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of a specially formulated epoxy resin and latent curing agent, and in terms of a coating process, a comma roll coating method is used for uniform film thickness in large area. The dielectric constant of ECF in high frequency range (0.5/spl sim/3 GHz) is measured using the cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. The dielectric constant is calculated by observing the frequencies of the resonant cavity modes. Calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of the epoxy matrix. The dielectric relaxation of barium titanate (BaTiO/sub 3/: BT) powder is not observed within measured frequency. An alternative material for embedded capacitor fabrication is epoxy/BaTiO/sub 3/ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming a capacitor partially in the desired part. However, the screen printing makes surface irregularities during mask peel-off. Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, a dielectric layer with improved thickness uniformity is successfully demonstrated. Using epoxy/BaTiO/sub 3/ composite ECP, a dielectric constant of 63 and specific capacitance of 5.1 nF/cm/sup 2/ were achieved.

High dielectric constant thin film embedded capacitor for suppression of simultaneous switching noise and radiated emission

Abstract: We have thoroughly investigated and experimentally demonstrated the great advantages of thin film embedded capacitors of high dielectric constant in reducing power/ground impedance and suppressing SSN and radiated emission up to a frequency of 1 GHz. About 10 dB or more suppression of the radiated emission was acquired for a wide frequency range, including high-numbered harmonics of the clock frequency, by using the thin film embedded capacitor of high dielectric constant.

Noise coupling to signal trace and via from power/ground simultaneous switching noise in high speed double data rates memory module

Abstract: We suggested the model to demonstrate simultaneous switching noise (SSN) coupling to signal and verified experimentally. There are two coupling mechanisms; one is the SSN coupling through the reference changing via, and the other is the SSN coupling through the signal trace. Through measurement and analysis, we confirmed that the worst SSN coupling occurs when strip lines have the signal via changing reference plane with SSN. Furthermore, we demonstrated that the power/ground noise coupling to the signal is reduced by placing the reference changing via at the position where the power/ground cavity impedance is low, or by adjusting the line length between two reference changing vias.

PCB power/ground plane edge radiation excited by high-frequency clock

Abstract: This paper describes the PCB power/ground plane edge radiation excited by a high-frequency clock, when it passes through power/ground plane pair by a through-hole signal via. For the analysis, the clock excitation mechanism was invested by TDR-TDT measurement and simulation with balanced TLM and via coupling model. Also, the power/ground plane edge radiation excited by sweeping from 100 MHz clock to 2900 MHz clock were measured. The power/ground plane edge radiation comes from voltage noise in the power/ground plane. From TDR-TDT investigations, we knew that a transition part in time domain makes the voltage noise, which has a strong relation with power/ground plane impedance depending on plane resonances and return current discontinuity of through-hole signal via. Therefore, the consecutive transitions of the clock make larger noise voltage and edge radiation. The PCB power/ground plane edge radiations of a clock depend on the power/ground plane impedance where the clock spectrum is varied. The higher power/ground plane impedance makes the larger power/ground plane edge radiation, when the clock frequency is fixed. In other words, the clock frequency and its harmonics go into the higher power/ground plane impedance range, the power/ground plane edge radiations are increased by maximum 35 dBm in near field measurement.