Need hardware advice: ULN2003A

[sayzer]

If you are not using all of the available arrays, you may want to make a parallel connection of the empty ones; thus providing a higher current both through the transistors and diodes.

[Christopher4187]

Actually, I am only using two of the seven available outputs. Are you saying to "gang" together something like 3 inputs and 4 inputs then 3 outputs and 4 outputs? Would this provide better protection if the collapsing field is in question?

[sayzer]

Since the load will be divided by the number of arrays you make in parallel, technically it would.

Datasheet has no detailed info on the diodes though, but the darlingtons support parallel connection and datasheet confirms this.


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[Christopher4187]

So, here is what I am thinking. If the field is 77mA and it is ganged together with three outputs, it is esentially like switching a coil current of approximately 26mA and the collapsing field has three different paths to go. This is below the 50mA that Melanie said she has used before. Is my thinking correct?

Thanks,

Chris

[sayzer]

Your thinking is "technically" correct of course.

Practically it "should" be correct. Since Melanie has a practical experience, so I say go for it.

[mister_e]

if you only use 2 driver... why not using SOT transistors/Mosfet instead?

[Christopher4187]

I am a creature of habit. If I have used an IC that I know works well and I have not had no problems with it, I will use it in future designs.