cctalk Digest, Vol 70, Issue 3

[CSquared]

----- Original Message ----- 
From: "Chuck Guzis" <cclist at sydex.com>
To: "General Discussion: On-Topic and Off-Topic Posts" 
<cctalk at classiccmp.org>
Sent: Wednesday, June 03, 2009 11:31 AM
Subject: Re: cctalk Digest, Vol 70, Issue 3


> On 3 Jun 2009 at 12:10, Dave McGuire wrote:
>
>>    The MAX232, if memory serves, is specced at 10V but usually tops
>> out at 8-9V in my experience.  I sure do love those chips. :)
>
> I get about +/-10 out of the MAX232Ns from TI, but I use 10 uF/25v
> caps instead of 1uF on them (just have more of them in my hellbox).
> There are also the cap-less models from Maxim (can't recall the part
> numbers) that are pretty tempting.
>
> Some modern equipment gives you +5/0 for "RS232" levels.  My DTV set-
> top-box with a DE9 on the rear panel  labeld "RS232" is such an
> example.
>
> Although, I suppose we're going to have to start calling it "TIA-
> 232".
>
> --Chuck
>
I was interested to see this comment because I have a DS232AS I need to 
replace, and the board it is on uses 10uF caps as you mention.  The Dallas 
Semiconductor data sheet mentions 10uF as an option "to reduce ripple". 
However, neither the Maxim nor the TI datasheets I've downloaded mention 
anything higher than 1.0uF.  I was concerned that if I substitute one of the 
other vendor's parts I would need to change the caps as well, but I gather 
this is not the case, so thanks for that comment.  I was concerned that the 
higher capacitance value might somehow load down the charge-pump circuitry 
or cause it to malfunction in some manner with a TI or Maxim part.
Later,
Charlie Carothers
My email address is csquared3 at tx dot rr dot com