questions about using ULN2803A darlington array

From schematics that people have posted online for using the ULN2803A, power should be supplied the pin labeled “COM”. If an external power supply is used to power the loads, should that power supply be used to supply the “COM” pin?

From what I have seen online, it seems that there is no need to calculate the current that needs to be supplied to the base pin as one would normally do when using individual bipolar transistors (noticed that there is an internal resistor connected to the base in the datasheet schematic.)

Nicknml:
From schematics that people have posted online for using the ULN2803A, power should be supplied the pin labeled “COM”. If an external power supply is used to power the loads, should that power supply be used to supply the “COM” pin?

The UCN2903A is designed to control loads connected to a common positive supply Vs. When the loads are inductive, such as a relay coil or motor winding, the COM pin should be connected to Vs. It serves to prevent damage to the i.c. when Vs is switched off and a large voltage spike may occur as the energy stored in the inductors is released suddenly.

Nicknml:
From what I have seen online, it seems that there is no need to calculate the current that needs to be supplied to the base pin as one would normally do when using individual bipolar transistors (noticed that there is an internal resistor connected to the base in the datasheet schematic.)

Correct, the inputs are designed to work directly with common logic families so the chip designers have already made those calculations.

Thanks.