The 12VHPWR connector, introduced in the earlier 2.0 revision of this document and the PCIe CEM 5.0 Specification, has been deprecated and replaced with the 12V-2x6 connector, as shown in th PCIe CEM 5.1 specification. While the 12V-2x6 connector specification is mechanically identical to the 12VHPWR connector in most respects, multiple updates have been incorporated into the newer, 12V-2x6 connector, to improve its reliability.
The chief improvements introduced in the 12V-2x6 connector include:
- The power pins have been lengthened and the sideband pins have been shortened in the PCB Header to ensure first-mate/last break engagement of the power pins. This mechanical revision is present in the 12V-2x6 PCB header component to ensure that the sideband pins engage only after the power pins are sufficiently mated.
- The sideband signals SENSE0/SENSE1 definitions, which signal maximum available power available from the PSU, have been updated, as shown in Table 3-6.
- The 150 watts power level now requires the SENSE0/SENSE1 pins to be shorted together in the power supply or the cable.
- When both SENSE0/SENSE1 are unasserted, as defined by their high-impedance Open-Open state, no power may be drawn by the load. This is new SENSE0/SENSE1 combination now defines the new 0 watt state, which was not present in the 12VHPWR connector. These updated SENSE0/SENSE1 combinations ensure that an Add-in Card may only draw power only when the power pins and the sideband pins are engaged and correctly asserted. The Open-Open condition signals that the PCB plug is either poorly seated or absent. These two conditions are now functionally equivalent. A PCIe CEM 5.1 Add-in Card will explicitly interpret the Open-Open SENSE0/SENSE1 stat as the 0 watt configuration, and it will not attempt to draw power from the cable.
- It is important that the power supply provide these updated SENSE0/SENSE1 encodings to the cable, to ensure compatibility with PCIe CEM 5.1 compliant Add-in Cards. See 3.3.1 for more details on SENSE0/SENSE1 encoding.