Bob Blick wrote:
>
> One thing that is sometimes mistaken for ESD is voltage breakdown in
> components. An example would be pic pin driving a transistor driving a
> load(for this example imagine a common-emitter with some base resistor). If
> the transistor is overvoltaged(due to inductive effects, perhaps)
> on turnoff, the pic is going to get crap sent back in on the pin it is
> outputting from, and also the ground is going to get yanked around by the
> emitter of the transistor(sometimes very significant!).
>
> -Bob

Yup. Clamp diodes on the 5V rail should be standard. One should also
bear
in mind that incoming spikes over 5V are nicely routed to the supply
rail
compliments of the protection diodes.

--
Friendly Regards

Tjaart van der Walt
mailto:tjaart@wasp.co.za
 _____________________________________________________________
| WASP International http://www.wasp.co.za/~tjaart/index.html |
|       R&D Engineer : GSM peripheral services development    |
|   Vehicle tracking | Telemetry systems | GSM data transfer  |
|    Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973    |
|              WGS-84 : 26010.52'S 28006.19'E                 |
|_____________________________________________________________|