Series internal resistance of Power Supply
You can estimate the effective internal resistance of the outputs from the load regulation specification.

For the fixed 5 V output, it's given as &lt;10 mV.

If the output voltage drops by 10 mV for a change in output current of 3 A, then the output resistance is \$\frac{10 mV}{ 3 A}\$ &lt;= 3 m&Omega;.