Re: High voltage protection for a breakout board.

Hi Arturo,

I don't know enough about electronics to say one way or the other
with regards to your direct question. However, there is something
that I think should be considered.

I am adding your breakout board to my CNC system which uses the
Hobby CNC board on LPT1. Your board is going on LPT2 to protect the
computer from the various experiments I plan on doing. The MACH3
software allows for pins 2-8 to be either inputs or outputs. As
outputs, your current board is good, however, if I want to use those
pins as inputs, I believe there is a problem with the isolation.
Perhaps you should consider running two circuits for those pins,
making them either inputs (isolated) or outputs (Buffered).

Just a thought.

Chris




--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Arturo E. Duncan"
<aduncan@c...> wrote:

> Group,
>
> I have been working a design for a new breakout board for general

use

> in cnc applications. The new design is based on the SN74LV245AT

IC,

> wicth acts as a bi-directional buffer and has ESD (Electro Static
> Discharge) protection for up to 2000V. I have been hoping to
> eliminate the opto-isolators with the use of these IC, and will
> greatly reduce the number of parts and simply assemble, thus

enabling

> the possibility to reduce the cost of the final product.
>
> I know for most interfacing applications this IC is a great

buffering

> device, but ¿would it be good enough protection from a possible
> failure of a stepper driver?
>
> The datasheet for this IC can be found at :
> http://www.cnc4pc.com/Tech_Docs/sn74lv245at.pdf
>
> Thanks,
>
> Arturo Duncan