Is it possible to plug a mini pci-e card such as the BCM970015 into an ExpressCard connector? Basically I am asking if I could put a mini pci-e card inside am empty ExpressCard card without any extruding components.

Information gleaned from wikipedia suggests they might be compatible.

  1. Physical
    • mini pci-e 1/2 size: 30×26.8×[1+components]mm vs expresscard 54: 34/54×75x5mm.
  2. Electrical
    • 1.5V or 3.3V
  3. Connection
    • 26 pins
    • direct connection to the system bus
    • USB 2.0 or PCI Express ×1 access (subset of connections provided by mini pci-e)

Edit: Clarify question.

Both Mini PCI Express and ExpressCard provide direct access to PCIe ×1 and USB 2.0, but do not provide physical PCIe ×1 or USB 2.0 connectors (I assume). Rather there is a custom connector (mini pci-e connector?), and access to which bus (PCIe or USB) depends on which pins are utilized, I assume.

I am asking two questions:

  • Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard slot.
  • Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard card.

By compatible, not only do I mean physical form-factor, electrical specification and connection/pin-out but also protocol. You can think if it as, "after plugging them together, will they just work, without any adapters".

For the record I am aware of a device such as PE3B, but am considering creating my own from a half-size mini pci-e card and a empty ExpressCard card. I've run out of mini pci-e slots in my laptop, but have a spare ExpressCard slot.

Edit: After accepting the answer, I've decided to post some useful links and notes in case anyone has similar questions.


ExpressCard notes:

Purchasing empty ExpressCard card "kits"


It is possible to bring the PCI-E 1x pins present in an ExpressCard slot to a Mini PCI-E connector, or even a normal PCI-E 1x connector. Gaming enthusiasts have succesfully used full size PCI-E graphics cards to add external GPUs to laptops.

However, all adapters I've seen either use a cable and a separate PCB assembly (ExpressCard to PCI-E), or they protrude a lot outside the ExpressCard slot (ExpressCard to Mini PCI-E).

Edit based on your clarification:

Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard slot.

No, the connectors and pinouts are different. Expresscard has a single row of 26 contacts, while Mini PCI-E cards have 26 contacts on each side with a notch in between.

Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard card.

There is no other connector inside a normal (not adapter) ExpressCard than the one that plugs to the ExpressCard slot. On the card side of the connector, it is soldered to the PCB. Since the pinout is different, it is not possible to directly swap the ExpressCard PCB with the Mini PCI-E card.

However, you should be able to do something similar to this (Wayback Machine Link): solder the required cables between an ExpressCard connector and the Mini PCI-E card, or even design a small adapter PCB. It should work, and it would be a very cool hack.

  • You haven't really answered my question, or I'm not interpreting the answer correctly (for example I've assumed that Mini PCI-E ×1 and PCI-E ×1 connectors are different). Anyway I've clarified my assumption, the actual questions, and why I'm asking. – user19087 Mar 5 '14 at 19:47
  • I've always found this counterintuitive, but there's no such thing as a "too thick" (lower gauge) connector wire, of course as long as they still fit in the casing (In reference to your comment about soldering cables)? – user19087 Mar 6 '14 at 17:45
  • @user19087: The wires for power (3.3V, 1.5V, GND) should be thick enough for the current requirements, while the wires for PCI-E signals could be much thinner. Differential pairs should run close together or even be twisted, also try to keep distances low. The only issue is that you may have to solder directly to the Mini PCI-E contacts, as connectors don't seem to fit inside. It seems you have researched all the details, hope it works if you try it! – Aleix Mercader Mar 7 '14 at 7:52
  • Thanks, these are great tips! For the wires I'm thinking of cannibalising an ethernet cable (pre-twisted). I think some manufacturer low-profile mini PCI-e connectors will fit inside. Just one more question: proper grounding would entail cross-connecting all the grounds from both connectors? – user19087 Mar 10 '14 at 21:39
  • @user19087: Yes, the grounds can be all connected together. Ethernet cable should work, but its rigidity can complicate the soldering (you don't want to lift a pad in the PCI-E card). You could use stranded (non-solid) Ethernet wire, or even the wires from an IDE cable, using the thick ones from a 40 pin cable for ground and power, and the thin ones from an 80 pin for the PCI-E signals, using 2 unseparated wires for differential pairs. – Aleix Mercader Mar 11 '14 at 7:26

There are commercial adapters available which will allow you to plug a PCI Express Mini Card into a ExpressCard slot. Seems to be something like what you are looking for?

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