Driving multiple electromagnets

[johnwasser]

@lpsd

wiring diagram . Is this how you meant it?

Yes.

@johnerrington

At 250mA Vces is 1.2V; if all 5 electromagnets are on you have 1.2V * (5*0.25A) = 1.5W
that is pushing the power dissipation for the chip.
You could glue on a small heat sink.

Yes, it looks like the "500mA per channel" is optimistic. Look at the "I_OUT vs. Duty Cycle (8 circuits active)" chart. If all 8 outputs are on solid you can only get about 110 mA out of each with plenty of cooling. To drive 8*250 mA you need to keep the duty cycle below about 40% and provide plenty of cooling.