Pmod connector power limit

[m3atwad]

Hello,

 

I"m looking at this board

https://reference.digilentinc.com/reference/programmable-logic/cora-z7/reference-manual?_ga=2.148724791.1278945709.1565030515-1644037005.1564093626

 

and in section 12 of the users manual it says that the pmod connector pins can source 100mA.  Does this mean each pmod can source 100mA?  so if there are 2x pmod connectors they can source a combined total of 200mA or the total current capacity of all pmod connectors is 100mA regardless of the number of connectors.

[jpeyron]

Hi @m3atwad,

My understanding is that there is a 200 ma bank limit as discussed on page 4(note #10) of the  Zynq-7000 All Programmable SoC (XC7Z030, XC7Z045, and XC7Z100): DC and AC Switching Characteristics. You can see that both pmod's I/O are connected to bank 34 as shown on page 8 of the schematic here.

The VCC and Ground pins can deliver up to 100mA of current per pmod as discussed in the reference manual in section 12 Pmod Connectors here.

best regards,

Jon

[m3atwad]

Ok I didn't know if the 3.3V came straight off the regulator so it was just a recommendation or it was bank associated.  I'm thinking about spinning a card to plug into the cora arduino headers.  I assume the 5V limit is just based on the regulator and if the DC power cable is plugged in?

[jpeyron]

Hi @m3atwad,

The VDD on the Pmod Ports is tied to the 3.3V power rail coming from the regulator. The 5V pin on the Arduino styled header comes directly from either the external or USB power based on the power jumper (JP3) setting and does not come from the power regulator. The schematic here on page 11 shows this. All of the I/O pins on the Arduino styled header go through the 3.3V regulator and are tied between bank 34 and bank 35 on page 8 of the schematic.

best regards,

Jon