PCB Currents: How They Flow, How They React

19. Current Distribution and Bypass Capacitors

19.1. Nature of the Problem

Consider the basic circuit shown in Figure 19-1. We have a power supply providing power to a Vcc plane and a VccRef plane. We have two logic devices deriving power from the planes: Driver (1) and Receiver (2). There is inductance in the power distribution path (not shown) as well as inductance at the point where the logic devices connect to the planes (L1 through L4). These inductances are inherent in the packaging of the devices as well as in the solder joint/pads where they connect to the planes. The power inputs and returns are shown for each device (P and R), and the ...