Connector type on GigaBlox Nano

Copied from a customer email

I went through your website and understood the following ,

· The daughter card is the PicoConn version with molex picoblade connectors

· There will be 4 cables for the Ethernet ports terminating with RJ 45 connector and one 4 pin picoblade with flying leads supplied along with the purchase of the daughter card

· There are only design files available for the daughter board no datasheet as such like the case for Gigablox nano is available.

· The port j7 in the daughter card is not used – please explain if it has any functionality.

· The J6 port is used for power with two Vin and 2 gnd pins .

Please validate our understandings.

There are two daughterboards we sell for GigaBlox Nano. PicoConn and RJConn. PicoConn is the daughterboard that uses Molex PicoBlade Connectors. RJConn uses RJ-45 connectors.

Yes, correct. Each PicoConn board comes with…

4 x BB-PBRJ1-8-0.3 : 8 Way PicoBlade to RJ-45, 0.3 meter cable. For connecting PicoConn with an RJ-45 port.
1 x BB-PBTL1-4-0.3: 4 Way PicoBlade to Tinned Leads (pigtail), 0.3 meter cable. For supplying power to GigaBlox Nano via the power connector on the PicoConn board.

To clarify, these are included in the package with PicoConn, you do not need to purchase them separately (though you can always purchase spares if you need to). We always supply cables with any of our boards that contain PicoBlade connectors. We do offer a custom cable service if you need a different length, but this usually has a minimum order quantity, a lead time, and is a bit more expensive.

Datasheets are available for both, you can find them at the links below.

J7 actually contains 3.3V, GND, MDIO and MDC. 3.3V is the internal 3.3V rail used on GigaBlox Nano. Some customers monitor this voltage to check GigaBlox Nano is working correctly, but this is not necessary, and most customers don’t do this. We also don’t recommend using that 3.3V rail for power other external devices, it only has a current source ability of around 300mA.

MDIO and MDC are the SMI signals that connect to the main chip on GigaBlox Nano. These are the signals that would be used to configure management functions (eg VLAN, port mirroring, etc) on GigaBlox Nano. However in this case, the chip on GigaBlox Nano does not respond to management functions anyway, so these pins are redundant. We included them on the design simply for future proofing, if later we are able to enable management functions on GigaBlox Nano. Simply leave this connector unconnected.

That’s correct, two pins are used for Vin, and two pins are used for ground. There are 3 reasons we did it like this.

  1. The wires used are quite thin, 28AWG, so using two pins allows us to increase the current carrying ability of the connection. This isn’t really a problem, even if you connected just one pin, GigaBlox Nano does not use much current and thus a single 28AWG wire works fine. However having a second is a good design measure.

  2. Having two connections means a customer can easily take the second pair of connections and use it to power something else, without needing a cable adapter. In this case, this means only a single pin pair would be used to power GigaBlox Nano, but again, this will work just fine due to the low current requirement.

  3. Using a four pin connector on GigaBlox Nano reduces overall BoM cost, as we use four pin connectors on our other boards. In fact, all our boards (apart from UbiSwitch and PoEBlox) use 4 pin Molex PicoBlade connectors for power.

Hope that helps.

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