ULN2003A to ULN2803A compatability

[bfgstew]

Hi all,

A simple question needing a simple answer.

I did have a ULN2003A driving a small stepper, but I had to swap this chip onto another project so it has left me with no driver for the stepper. The question is can the ULN2803A step in its place, I know its an 18 pin package and the ULN2003A is a 16 pin package, if it is placed in the 16 pin socket with pins 1 and 18 not in, would it still work like the ULN2003A????? I have it wired up as per the manual 3 page 16, any ideas, apart from buying some ULN2003A's as I have about 20 ULN2803A's to hand.

 

[womai]

Should work. The 2803's pins 2...9 go where the 2003's pins 1...8 were. I.e. pins 1 and 18 of the 2803 will be left open. No issue with that.

 

[bfgstew]

Thanks Wolfgang, I just needed confirmation really and didn't think the floating pins would be an issue.
Off to give it a try!

Stewart

 

[bfgstew]

Seems like we have success, just putting it through its paces now and just coming up to the end of its first run. .........

 

[westaust55]

It is always helpful to read the datasheets when dealing with and comparing components.

The only difference is the number of channels.
These channels are only transistors so there is no problem leaving unused channels floating.