Sorry I didn't post an answer to this before now, I got roped into
looking at
something else.

As you may know this is to power a microphone pre-amp and other related
circuitry. The calculated maximum input from the microphone is going to
be
35.52 Volts pk to pk, and this cannot be altered. Therefore to avoid
clipping
the signals I really do need a + / - 18 V supply.

The good news is I don't want to try and generate + / - 18V from the
3.3V
supply anymore, I will generate it from the six AA batteries in series
(~9V),
but the drop out voltage should really be less than 6V.

Does this make the task any easier?

Thanks

Graham

> -----Original Message-----
> From: Tom Handley [SMTP:tomhandley@MINDSPRING.COM]
> Sent: Thursday, March 21, 2002 2:53 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: [ee]: +/-18 Volt Supply
>
>    Graham, could you ask your `analog guy' why he needs +/-18V? Normal
> linear supplies are +/-15V. It almost sounds like he has 15V
> regulators
> on the analog side. If he can use +/-15V, or better yet, +/-12V, you
> have many more options. Ask him if one of the above supplies would
> work. If so, I have some ideas that may be of help. Note, I'm
> assuming he's working with a common input range of +/-10V.
>
>    As far as the other supplies, as others mentioned; Linear, Maxim,
> TI, National, and others have very efficient ICs that will generate
> those voltages with a minimum of components. Take a look at some of
> their web sites and Switcher CAD porgrams.
>
>    - Tom
>
>
> ----------------------------------------------------------------------
> --
> Tom Handley
> New Age Communications
> Since '75 before "New Age" and no one around here is waiting for UFOs
> ;-)
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body