Re: Can I do this with a uProcessor?


Spehro Pefhany <speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

> Any kind of ESD through the switch that that doesn't get shunted
> to ground can cause a CMOS processor to latch up, and likely die.
> There will be fingers on the switches, and static electricity. A
> 0.1 cent resistor is cheap insurance.

Latchup is a serious issue, especially with some Analog Devices ics
where they fail to warn you the chip is sensitive and will die, like
some of their DDS chips. So now I use a buffer like a 74LS04 or
2N2222 inverter between the chip and the outside world.

ESD is a big problem, even with parts that are rated for body or
machine discharge. You can always find a discharge that is larger.
For example, walking across a carpet in Colorado in the winter can
easily generate 1 inch sparks.

The voltage is high enough, so wouldn't it simply arc over a small
smd part? What kind of resistor would solve that problem?

[...]

> Best regards,
> Spehro Pefhany

Regards,

Mike Monett
.

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