The Fairchild 74HC595 datasheet specs a max current of
35mA per pin though I wouldn't get anywhere near that
with out a pretty gentle duty cycle.  The dip package
has a 600 mW limit, and the SO's is 500 mW. 

I've run a number of tests on it because I was
concerned.  With all 8 outputs constantly driving LEDS
at 10 mA for 24 hrs there was very little heat
increase (a couple degrees F) so the 500 mW limit may
be conservative.  This was with both Fairchild and ST
parts.  Any kind of <100% duty cycle is going to help
here as well.

One thing to be carefull of is inrush current and
spikes on the clock and serial in pin.  I use a 1K
limiter and 100K to ground on both RCLK and SERIN.

Phil

--- PicDude <picdude2@narwani.org> wrote:
> On Thursday 26 May 2005 04:30 pm, phil B scribbled:
> > My favorite answer is a 12F509 + 2 74HC595s (to
> drive
> > up to 16 LEDs) but I suspect thats not what is
> being
> > looked for.
> >
> > Phil
> 
> 
> Doesn't the 74HC595 not have the current output
> capability of a PIC?  IIRC it 
> was something like 5-6mA for the 74HC595, which IMO
> is not much for driving 
> LED's properly.  But of course, it depends on the
> specific LEDs and 
> application of the OP.
> 
> Cheers,
> -Neil.
> 
> 
> -- 
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
> 


		
__________________________________ 
Do you Yahoo!? 
Yahoo! Small Business - Try our new Resources site
http://smallbusiness.yahoo.com/resources/
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist