This is a multi-part message in MIME format.

--===============2147387149==
Content-type: multipart/related;
	boundary="Boundary_(ID_GhVlfLdpyxNOLxbd/hbUOg)"; type="text/plain"

This is a multi-part message in MIME format.

--Boundary_(ID_GhVlfLdpyxNOLxbd/hbUOg)
Content-type: text/plain; format=flowed; charset=iso-8859-1;
	reply-type=original
Content-Transfer-Encoding: quoted-printable
X-MIME-Autoconverted: from 8bit to quoted-printable by pch.mit.edu id k5RCdJhc023858

>>Note that Maxim and Analog devices have high frequency
>>switching TEC controllers that can give low ripple with
>>very small inductor and capacitor values.

> Yeah, I'm needing to do it with Radiation Hardened devices though,=20
> as it is
> going to orbit the moon. If I use the "correct" device then I would=20
> be stuck
> with something around 50kHz!!!, based around a Rad Hard version of a=20
> UC1845.
> May yet just use a mil-spec one that is speced to go to 500kHz, as=20
> that was
> used for another purpose on a previous mission.

I've just had a fuller skim of the Maxim app note I mentioned

        http://www.maxim-ic.com/appnotes.cfm/appnote_number/1757/

It's highly appropriate to your application and worth a look.

They mention the specific inductors used for smoothing.

    " Each side of the H-bridge drives a lowpass filter, which=20
consists of a 10=B5H inductor followed by a 10=B5F ceramic capacitor that=
=20
feeds the TEC. A supplementary 10=B5F across the TEC eliminates the=20
possibility of residual spikes in differential mode. It's not=20
necessary to oversize the inductors. Model CDRH6D28 by Sumida provides=20
10=B5H in a package 6.7mm square and 3mm thick. A 20m shunt is inserted=20
for measuring the TEC current. Rough filtering (7.5 and 1=B5F) provides=20
a clean 20mV/A signal by eliminating a good part of the switching=20
frequency ripple."


        RM


--Boundary_(ID_GhVlfLdpyxNOLxbd/hbUOg)
Content-type: image/gif; name=ohm.gif
Content-disposition: attachment; filename=ohm.gif
Content-Location: http://media.maxim-ic.com/images/ohm.gif
Content-Transfer-Encoding: base64

R0lGODlhDAAJAJEDABISEomJicnJyf///yH5BAEAAAMALAAAAAAMAAkAAAIgnBUZYi3AxosGhDYC
cBDP03GUhWle+BnLxF4ZAAsPfBUAOw==

--Boundary_(ID_GhVlfLdpyxNOLxbd/hbUOg)--

--===============2147387149==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Disposition: inline
Content-Transfer-Encoding: 7bit

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

--===============2147387149==--