Abstract: Electronic devices to output signals at different frequencies are mounted to a circuit board that has a group of layers, where the group of layers include reference plane layers and signal layers between the reference plane layers. A first signal layer has conductive traces having a first dimension to communicate the signals at a first frequency, and a second signal layer has conductive traces having a second, different dimension to communicate signals at a second, different frequency. The first and second signal layers are successive layers without any reference plane layer in between the first and second signal layers.

Abstract: A circuit board having a load is inserted into a chassis of a digital system while the system remains in operation. During insertion, a ground potential is provided to the circuit board. Next, one or more voltage potentials are provided, however, no electrical path is provided from the voltage potentials, through the load, to ground. An enhancement voltage is provided to the circuit board, allowing the load to charge. Finally, a backplane is connected to the circuit board after the load has charged. The circuit board includes a soft start circuit that allows the load to charge gracefully after the enhancement voltage is provided. In one embodiment, the soft start circuit includes an RC circuit connected to a switch which gradually turns on as the RC circuit charges, thereby providing an electrical path from the circuit board load to ground through the switch. The switch may be a MOSFET.

Abstract: A noise suppression apparatus for a printed circuit board (PCB) having two PCB pad regions, each containing a boundary pad region and a mounting pad region, wherein both boundary pad regions contain via connections. A decoupling capacitor is coupled to both mounting pad regions. Both boundary pad regions are solder mask except the mounting pad regions and the via connections.