The new address for this page is:
http://www.interfacebus.com/Design_PCI_Card_Size.html
The standard PCI card form factor is 107mm x 312mm [4.2" x 12.283"]. The low profile version of the PCI board ranges from 64.41mm x 119.91mm to 64.41mm x 167.64mm [ 2.56" x 6.6"].
The Peripheral Component Interface 'PCI' Bus was originally developed as a local bus expansion for
the PC (ISA) bus, and was coined the PCI Local Bus. The spec started as an add-on to the ISA form
factor with the PCI requiring its own connectors. The PCI specification defines the Electrical requirements
for the interface. No bus terminations are specified, the bus relies on signal reflection to achieve a valid voltage level threshold. The first version of the PCI bus ran at 33MHz with a 32 bit bus (133MBps), the current version runs at 66MHz with a 64 bit bus. The PCI bus operates either synchronously or
asynchronously with the "mother Board" bus rate. While operating asynchronously the bus will operate
at any frequency from 66MHz down to (and including) 0Hz. PCI is an unterminated bus, the signal rely on signal reflections to attain there final value.
The PCI connector pins define how the card draws power from the Mother Board. Pin arrangements are defined for +5 volts, +3.3 volts, or +5 and +3.3 volts. The +5 volt connectors and boards are Keyed, so that 3.3 volt cards may not be inserted. The +3.3 volt boards are also Keyed but in a different location on the connector, so that 5volt cards may not be inserted. However the difference between the two card types resides with the signaling protocol they use, and not with the power rails. Refer to the PCI Bus Pinout page for signal descriptions and connector pin-out information.
The top picture show a combination PCI/AT card; for reference, J1 (sides A/B) represent the XT bus, J2 (sides C/D in addition to J1 A/B) represent the PC AT (ISA) bus.
There is also another style of card called PISA; PCI+ISA (not shown above). It's a combination ISA, and PCI bus in a short card form factor. In PISA's case the ISA and PCI fingers are on top of each other (but offset). You need a back plane designed to accept PISA cards, to use the PISA card. The PISA bus is used as an Industrial Embedded Computer Bus, not a consumer Personal Computer bus.
The card [Board] sizes shown do not represent the absolute card size possible, but represent the general size which may be encountered. The size of a PCI card is represented by the second graphic, which depicts a PCI bus expansion card without the ISA bus.
Engineering Key Words: PCI, Peripheral Component Interface, PWB, CCA, Circuit Card, Printed Wiring Board, Form Factor, Mechanical, Mechanics, Height, High, Long, Personal Computer, AT Bus, Local Bus, PC Bus Board Dimensions, PCI Bus Board Dimensions, ISA Bus, How tall is a PCI card, How long is a PCI card.
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