Device Family: Arria® II GX, Arria® II GZ, Arria® GX, Cyclone® II, Cyclone® III, Cyclone® IV E, Cyclone® IV GX, Stratix® II, Stratix® II GX, Stratix® III, Stratix® IV E, Stratix® IV GT, Stratix® IV GX, Stratix® V GS, Stratix® V GT, Stratix® V GX

Type: Answers

Area: Component



Can I connect multiple power or GND pins to their planes through a single via with Altera devices?

Description

No, you should not connect multiple power or GND pins to their planes through a single via with Altera® devices. Each power or GND pin should have its own dedicated connection to the plane.

Connecting multiple power or GND pins together and sharing a single via to the plane increases spreading inductance. Increased spreading inductance reduces the Power Distribution Networks (PDN) ability to supply instantaneous current to the device. This can result in a voltage drop at the FPGA pins which is seen as noise. Decoupling capacitors should also have their own dedicated vias to the power and ground planes.

Figure 1. shows an example of multiple FPGA pins sharing a single via connection to a plane on the left, and also the recommended method on the right.

Figure 1. BGA pad via sharing

Figure 2. shows an example of multiple decoupling capacitors sharing a single via connection to a plane on the left, and also the recommended method on the right.

Figure 2. Capacitor pin via sharing