PCIe-6612 +5V output

[ycg44]

I have been using the +5V output of the PCI-6602 for years to power a little logic upstream of the counters.  When I had to switch to the PCIe-6612, I checked the spec of the +5V output and it was also good for 1A.  I am only using about 100mA and now with the PCIe-6612, the +5V output is drooping down to 4.7V.  Any idea as to why and what I can do about it?

Steve Hope

CompuFlow Solutions

602-625-4673

[santo_13]

Probably the board is overheating and causing the regulator to go into thermal shutdown often causing the voltage to droop.

There was another post where the user's PCI card did not even have 5V at the terminal, when sent for repair, they figured out the power supply section was damaged.

[ycg44]

I am afraid it is more systemic than that.  We have tried three different interface cards (5V, 100mA load) and three different PCIe-6612 cards, all with the same 4.7V results.  When we change to a PCI-6602, the supply is back to 5V.

Steve

[santo_13 · Accepted solution]

Huh, interesting, the specifications document describes the peculiarity of the 5V supply (moreover 4.25V to 5.1V is still expected) and this 5V is shared with the DIO/PFI lines and based on those usages, you would see voltage droop here too.

Since you're measuring 4.7V, it is still within specifications, I believe you expected it to perform the same as 6602 but the specification begs to differ.

[ycg44]

Wow, went through specs several times and did not see that.  It clears up the mystery.  Thanks!

Steve