Alan Bloom wrote: >> I'm not sure what you mean about the regulator not being "quiet". The LM723 >> is a simple linear I.C.; no switching noise and no acoustical noise. >... > >It's true that the 723 is a really ancient IC - it was designed back in >the 70's I believe.
Ancient is not always bad, because the 723 was way ahead of its time. The 723 survived the introduction of convenient 'drop-in' regulator ICs like the 7812 and 317 because that first generation of 3-pin regulators had inferior performance in critical applications. Only in more recent years have more modern 3-pin and 5-pin regulators moved ahead of the ancient 723. When production lines changed over to lead-free manufacturing processes, many of those very early ICs were discontinued. The 723 is one of the few that 'made the cut' because there is still nothing else quite like it. >It is also true that there are some pitfalls with using it that can >trap the unwary. But with proper design it can be made to work just >fine. > The 723 is not a plug-and-play circuit block; it's really a 'kit of parts' on a chip, with all of its functions - voltage reference, op-amp, compensation - accessible on separate pins. These functions can be configured in several different ways, which means that the 723 will always require some good old 1970s-style analog circuit design... which includes plenty of opportunities for the designer to make mistakes. The classic reference for this style of detailed, up-close circuit design is 'The Art of Electronics' by Horowitz and Hill - one of the few college-level engineering texts that belongs on the workbench as well. Highly recommended. -- 73 from Ian GM3SEK http://www.ifwtech.co.uk/g3sek ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
