IMSAI News?

From: Richard Erlacher <edick_at_idcomm.com>
Date: Mon Jun 17 00:23:58 2002

If you poke around in the DigiKey catalog a little bit I'll be you can find
the TO-220 switchers that somebody or other sells. There are also some that
sit on TO-3 footprints, though neither type is as small as the genuine
package. Another problem is that the small switchers still only put out about
a half to maybe one ampere, and I've got a few S-100 boards that have two or
three three three-amp regulators on them. Several others have a TO-220 for
each of four banks of SRAMs.

Dick

----- Original Message -----
From: "Tim Shoppa" <classiccmp_at_trailing-edge.com>
To: <cctalk_at_classiccmp.org>
Sent: Sunday, June 16, 2002 5:09 AM
Subject: Re: IMSAI News?


> > The power supply and its management was the least of your worries with
their
> > hardware. However, if your board required +/- 15, which was pretty easily
> > regulated from the +/- 16, which was seldom limited to 16, you'd be in
real
> > trouble with the 12 volt bipolar supply.
> >
> > Further, I'd say, though it's not "new" nowadays, it was practiced only a
> > short time in the life of the S-100. I think the deviation from the
standard
> > practices, not necessarily the "standard," was what led to its death,
> > actually.
>
> If I was going to do it today, I'd stick with the ~8V unregulated bus and
> use a small buck switching regulator on each card. You get all the
efficiency
> of a switcher, and compatibility with older stuff.
>
> With "Simple Switchers" from NatSemi (or equivalent from Motorola/Onsemi/
> TI etc.) it's very easy to do. What's really good is that many of the
> electronics distributors which let their inductor selection whither away
> over the years now have excellent selections of inductors - some of which
> they keep in stock! :-)
>
> Tim.
>
Received on Mon Jun 17 2002 - 00:23:58 BST