IMSAI News?

From: Richard Erlacher <edick_at_idcomm.com>
Date: Tue Jun 18 08:38:17 2002

There are some "ready-to-use" products in this line from NS. That gives you a
PCB about 1.5" x 0.5" x 0.6" high with unregulated power in and regulated
power out, with a common connection at ground. I think they call this an
evaluation unit, but they sell 'em.

There's still no ideal solution. The smallish NS products are still too
large, as are the PowerTrends products. I guess it depends on how much of a
kludge you're willing to put on your boards. I personally believe the S-100
is S-100 and it should be run from an unregulated supply using the on-board
regulators for which the original design made provision. If you want
something else, you can use something more modern, but don't try to fool
yourself in to believing it's S-100 when you're done.

I rather believe that Todd Fischer's goal in using a switcher was based on the
low cost of the "PC" switcher, which is grossly overrated, power-wise, and its
relatively low shipping weight. My belief is that if you want to run classic
hardware, you should run it as shipped. If you don't need to run the classic
hardware, then run a simulator. It's less costly and runs lots faster.

Dick

----- Original Message -----
From: "Tim Shoppa" <classiccmp_at_trailing-edge.com>
To: <cctalk_at_classiccmp.org>
Sent: Monday, June 17, 2002 7:14 PM
Subject: Re: IMSAI News?


> > 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.
>
> Yeah, Powertrends (now owned by TI) makes them. I prefer the NatSemi
> simple switchers over the all-in-one one Powertrend units, which are
> are largish chunks of epoxy and metal on the end of three TO-220 legs.
>
> > 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.
>
> The 150kHz and 250kHz NatSemi units are 5-legged TO-220's and do 3A and
> 5A quite comfortably. You need room for the inductor, of course, but
> small ones are very readily available.
>
> Tim.
>
Received on Tue Jun 18 2002 - 08:38:17 BST