If you want high efficiency you might consider a switching regulator.
There are versions available w/ low quiescient current and features
like logic controlled shutdown, etc. But they're more complex than LDO's
and tend to use more space. But there's some quite simple ones
such as the LTC1503-2 from Linear Technology, which requires no
external inductors and just 4 small caps wired to it.

Disadvantage of an LDO is all the current must flow through the input;
hence, they exhibit lower efficiency.

-Dave






Dale Botkin <dale@BOTKIN.ORG> on 04/11/2000 10:50:16 PM

Please respond to pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>

To:   PICLIST@MITVMA.MIT.EDU
cc:    (bcc: David E Arnold/SYBASE)
Subject:  Re: [OT] Samsung Parts (voltage regulators)




On Wed, 12 Apr 2000, Russell McMahon wrote:

> Of particular interest to me was a TO92 regulator (KA76L05Z) with low
> dropout specs and max input voltage apparently similar to the LM2936 (which
> I use due to its very low quiescent current, very low dropout, higher than
> many max input voltage) and at a MUCH lower price from RS.

I just stumbled upon the ICL7663, programmable (2 resistors), low dropout,
<10uA quiescent current, logic controlled shutdown, and a tempo output
that looks like it could be used for generating LCD contrast voltage.
Works like a charm. Is there something else I should look at as well?
Typically I want to use either 4xAA or a 9V battery and have it last for
many months, so the 78L05 isn't a particularly good choice.  The 7663 cost
me a couple of bucks, but if there's something equivalent in performance
and cheaper or easier to get, I'd love to hear about it.

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
                -- Isaac Asimov