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Re: [N8VEM-S100:4453] MAX-232 chips

On 7/1/2014 7:42 PM, norwestrzh via N8VEM-S100 wrote:
<https://groups.google.com/d/optout>I just learned that apparently (I
have not looked at the data sheet myself) MAXIM has changed the function
of pin 2 on their serial line driver chip.  The old configuration was a
polarized cap. tied to gnd. (that's the way I always wired them), and
their data sheet now shows the cap. tied to vcc (I'm told).  Could
account for the heat, and short service life!!! *grin*  Bottom line is
check the data sheets, or stick with T.I. 232 chips (they still work the
same old way).  Wonder why they did this????


The CAP has a lower voltage across it when wired to VCC. Otherwise it doesn't matter. It's just part of the charge pump.

There are also newer variants of the MAX232 that don't require polarized caps which I prefer.