Bypass Capacitor Selection for High-Speed Designs

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In order to guarantee better performance from high-speed digital integrated circuits (ICs), manufacturers are tightening power supply noise margins. With lower power supply noise margins, the designer needs to pay closer attention to local bypass capacitor selection.
As bus speeds increase and switching times decrease, proper selection of local bypass capacitors for high-speed digital ICs is becoming increasingly complex. With wider parts becoming prevalent in cache subsystems, the amount of current required from the
bypass capacitor to decouple noise from the current transients switching across the power bus is increasing. At the same time that the current transients become larger, the need to choose smaller capacitance values is becoming more important. Smaller capacitance values offer lower series inductance