ESD and the NanoBoard 3000

Parent article: NanoBoard 3000

The NanoBoard 3000 contains many digital devices that are highly sensitive to electrostatic discharge (ESD). To provide a level of protection against such discharge, the motherboard incorporates shielding for the following metallic-based components that are routinely handled:

• RS-232 port
• Host USB port
• User USB port
• USB Hub ports
• SVGA port
• Ethernet port
• MIDI interface ports
• PS/2 Keyboard and Mouse ports
• Power toggle switch.

Each of these components is connected to a common SHIELD point. When the NanoBoard 3000 is connected to a PC using the USB connection, the component SHIELD is essentially tied to the PC's chassis ground, and it is through this ground that any build-up of electrostatic charge will be dissipated (discharged). If the NanoBoard 3000 is not connected via USB, then the electrostatic charge is coupled via a 10M resistor and 4.7nf capacitor to logic ground (GND).

In addition, ESD, RFI/EMI and aggressive earth management requirements are achieved through protective shield nets – made available to the motherboard and peripheral board via the mechanical standoffs. This not only ensures the protection of the NanoBoard 3000 against damage arising from ESD events, but also prevents spurious resets due to 'ground bounce'.