Neil schreef op 02-Dec-14 4:36 PM:
> I want to amplify some TTL-level signals for better noise immunity
> through about 10'-15' of wire through a vehicle, and trying to figure
> out what good options there are.  The data being transmitted is a custom
> signal (not exactly async serial, and not exactly PWM) of approx
> 50-100khz, at 5V.  Only one data-line out and one data-line back in.  It
> works now, but noise issues we've experienced in other areas has me
> worried, and the board is being revised currently, so I want to add this
> also.  The wiring/harness is pretty much set in stone so I can't really
> twist, shield or add wires for differential signaling, etc.  The
> electronics at both sides of the line is pretty much all I can change.
>
> First thought is 74xx245's etc, but have the impression they're really
> for strengthening signals for driving higher loads over short distances
> (ie: still chip-to-chip comms).  The last time I used these was  a few
> decades ago with a Z80 processor.  Not sure I should use it for long
> wires across devices.  Another option is to use discrete transistor
> push-pull drivers.  Also, I'm sure I can use a MAX3232 or similar for
> this.  But are there any other better options?  Looking at digikey gives
> me 10k+ options, and filtering by package, supply-voltage, cost, etc
> still nets me a couple thousand options.  Favourite devices?
>
> Cheers,
> -Neil
>
>
>
>
>
I'd suggest a balanced driver/receiver pair for each signal, RS485=20
driver chips are cheap and readily available.

Wouter
--=20
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