Today's fast-rise-time signal lines need proper impedance matching to minimize reflections, and the most common technique engineers employ to achieve this is by placing a series resistor in the line. This method works, but incurs a power-consumption cost since the resistor draws continuous dc current. With the |Z|-chip from AVX/Kyocera you get the impedance matching of the resistor, but with a series capacitor included as well. This capacitor blocks dc current flow, allowing the ac signals to pass to ground, while stopping quiescent dc flow and dissipation.
You select the resistor of the device to make the impedances match, and then the resistor and associated capacitor set the time constant. AVX offers ±20% capacitor values of 33, 47, 68, 100, and 150 pF, along with ±10% resistors of 22, 33, 47, 51, 100, and 150W. Although you could use separate resistor and capacitor chips, the integrated parts save board space and reduce parasitics which can affect system performance. The 0603-size chips are US$0.035 (100,000).
You select the resistor of the device to make the impedances match, and then the resistor and associated capacitor set the time constant. AVX offers ±20% capacitor values of 33, 47, 68, 100, and 150 pF, along with ±10% resistors of 22, 33, 47, 51, 100, and 150W. Although you could use separate resistor and capacitor chips, the integrated parts save board space and reduce parasitics which can affect system performance. The 0603-size chips are US$0.035 (100,000).
