SOIC-8 IC input pins small spacing at high voltage

Question

I'm looking at a high common mode voltage difference amp (AD629). The input voltage between the two input pins next to each other will be 150VDC. Normally the pads should be bigger on the PCB than the actual pin size. So between these two pads is at most 0.6mm space.

I think this isn't enough. Do I have to make a cutout in the PCB? Why do the manufacturers design something like this? One or two NC-pins between the input pins would be very helpful. Thanks for your help.

score 2 · Answer 1 · answered Jul 18 '19 at 00:53

2

Would a small dab of an insulating / potting compound between the pins be out of the question?

answered Jul 18 '19 at 00:53

hacktastical

49,832
2
47
138

1

Best answer, applying something like MG #4223 would raise the voltage to close to 700V at 0.6mm. https://www.mgchemicals.com/products/conformal-coatings/4223-polyurethane-conformal-coating You can buy really small bottles for about $10-15 on Amazon. – Jack Creasey Jul 18 '19 at 04:41

score 1 · Accepted Answer · answered Jul 17 '19 at 22:18

See this related but not duplicate question here on electronics.stackexchange.

The first answer has a chart, that lists 0.6mm as an acceptable distance.

Keep in mind that the chart is mostly safety related -- if you're worried about leakage causing accuracy issues, that's a conversation between you and ADI.

SOIC-8 IC input pins small spacing at high voltage

2 Answers2