Showing papers by "Hyungsoo Kim published in 2001"

Separated role of on-chip and on-PCB decoupling capacitors for reduction of radiated emission on printed circuit board

Abstract: The power/ground fluctuation is known as a significant source of radiated emission. We discuss the separated functions of on-PCB and on-chip decoupling capacitors on the suppression of electromagnetic radiated emission. Due to the different ranges of parasitic inductance and the different locations of the on-chip current drivers, on-PCB and on-chip decoupling capacitors exhibit separated frequency characteristics in terms of suppression efficiency of radiation. The roles of on-PCB and on-chip decoupling capacitors are estimated by circuit simulation and a simple antenna model, and are confirmed by experiments. It is found that the on-chip decoupling capacitors are mainly effective for the suppression of radiated emission over 100 MHz frequency. Increase of the on-chip decoupling capacitance and decrease of the parasitic inductance of the package produce an improved suppression ratio at high frequency range. Combined placement and sizing of the decoupling capacitors have achieved more than 10 dB suppression of the electromagnetic radiated emission over a wide spectrum range.

Reduction of crosstalk noise in modular jack for high-speed differential signal interconnection

Abstract: Crosstalk noise has become a significant problem in the design of high-speed digital interconnections. In this paper, we demonstrate a crosstalk reduction method, which has been successfully applied to the design of a CAT-5E modular jack. The CAT-5E is a newly adopted cabling and connector standard for advanced cabling network systems to assure more robust, reliable and high-speed operation, which is based on differential mode signal transmission using unshielded twist pair (UTP) cable. The improved design of the modular jack shows minimal crosstalk noise and return loss over a wide range of manufacturing conditions. The improved crosstalk characteristics of the modular jack were accomplished by inserting embedded capacitors on the printed circuit board (PCB) of the modular jack. The embedded capacitors compensate for the unbalanced capacitive crosstalk that occurs in the plug and insert. In particular, the embedded balancing capacitor is designed to have maximum capacitance, with limited PCB area, by using a double-sided PCB design. Less than -45 dB near-end-crosstalk (NEXT) was achieved after the crosstalk noise compensation, satisfying the CAT-5E specification for frequencies up to 100 MHz.

Equivalent circuit representation and dimension reduction technique for efficient FDTD modeling of power/ground plane

Abstract: We rigorously present a time-domain simulation method for the prediction of the simultaneous switching noise (SSN) in high-speed digital systems, using power/ground plane modeling of an arbitrarily shaped board or package.

Controlled power/ground noise on multi-layer digital printed circuit board using adaptive CMOS output driving scheme

Abstract: Even though the CMOS output drivers are the major source of the simultaneous switching noise in the highspeed digital printed circuit board, the output driving current could not be controlled by the printed circuit board designer. Hence, we introduce a new CMOS adaptive output-driving scheme, providing the customized controllability of the power/ground noise and the signal rise time to the printed circuit design. The proposed output-driving scheme has successfully demonstrated the adaptive operations with wide loading conditions from 6 pF to 22 pF. Also the driver has exhibited the controllability of the power voltage noise from 102.7 mV to 234.7 mV and ground voltage noise from 45.7 mV to 96.3 mV, as well as the signal rise time from 4.2 ns to 2.1 ns.