cctalk Digest, Vol 70, Issue 3

Ethan Dicks ethan.dicks at
Wed Jun 3 11:19:15 CDT 2009

On Wed, Jun 3, 2009 at 12:10 PM, Dave McGuire <mcguire at> wrote:
>  Very true; I was talking about the formal spec.  I *think* the spec
> actually says +3V to +15V and -3V to -15V, but I don't recall for sure and I
> don't have it in front of me.

That is my memory, too, but I don't have it in front of me either (but
I used to make datacomm hardware, so I'm reasonably certain of it).

>>  I am pretty sure that the MAX232 can't get things better than
>> about +/-10V (but I could be mistaken about that).
>  The MAX232, if memory serves, is specced at 10V but usually tops out at
> 8-9V in my experience.

There you go... that makes sense.  I've even been known to tap a few
mA off of one of the negative charge pumps for LCD bias voltage for a
serial-interfaced LCD panel (192x64 pixels).

>  I sure do love those chips. :)

Yep.  I love 'em too, especially when they can let me stick with a
+5V-only design.  Not as beefy as 1488s and 1489s, but a snap to use.


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