SpaceWire can also be run over printed circuit boards (PCBs) including backplanes. Because of the high-speed of SpaceWire signals which have a bandwidth of over 1 GHz (at 200 Mbps the signal frequency is 100 MHz and that of the signal edges around ten times this, giving 1 GHz) care has to be taken with the PCB layout. The following guidelines should be adhered to:

  • The PCB tracks must have 100 ohm differential impedance
  • Track pairs well separated from other tracks
  • No right-angle turns
  • Minimal use of vias
  • Each signal of the differential pair to be tracked identically and kept to the same length (< 5 mm)
  • Data and strobe signal pairs to be of the same length (< 5mm)