ACS714 current sensor

hasanrubaie · June 25, 2009, 7:17pm

Hi,

I’m planning to use “ACS714 current sensor” for a +/-30A range . Now what confuses me is the fact that the sensor’s package is SOIC8 and referring to the sensor datasheet the pin diameter/width is about 0.65mm…pins in this width usually can’t take more than 1amp!

Since I’ve already seen a built module https://www.pololu.com/catalog/product/1187 now I can believe this thing should be functional…anyone here please could explain to me how did that happen!

And also when building a PCB design, you need 42mm trace for 30AMP according to: http://circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/
which is much wider than two pins and the spacing between them in this package …

Thanks,
Hasan

jan · June 26, 2009, 9:37pm

Hello,

An SOIC pin can take a lot more than 1A. Also, two pins are used to carry the current.

For the PCB, some of the current is carried on each side. The calculation you did is probably for the default temperature rise; with 30A, the board could heat up more than 10 degrees. If you are routing your own board, make sure you maximize the copper area and use thick copper!

- Jan

hasanrubaie · June 30, 2009, 5:55pm

I actually don’t know how much current a SOIC package can take; I made my approximation based on the pin width. Anyway, thank you for your help, much appreciated!
Hasan

EmilyP · June 30, 2009, 9:03pm

For some reason the data sheet for the pololu current sensor is not opening on my computer. How do I connect my wire of interest to the sensor. Which hole should I put it through? Should I put it through more than one hole. Thanks.

hasanrubaie · June 30, 2009, 11:38pm

Here: http://www.allegromicro.com/en/Products/Part_Numbers/0714/0714.pdf
…Check the typical application page 1

jan · July 1, 2009, 5:10pm

I’m able to see the datasheet. What browser are you using, and is it still not working for you?

The multiple connection holes are for your convenience; you can connect to whichever holes best match your wire sizes. In general, you probably want to use the thickest wires you can if you expect to be getting close to the 30A.

- Jan