Forums

Buck switcher chips

Started by Phil Hobbs July 19, 2013
On Fri, 19 Jul 2013 10:59:21 -0700, Jim Thompson wrote:

> On Fri, 19 Jul 2013 13:47:06 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >>So we've got the +-40V sorted out, thanks to all. The next bit to >>re-examine is the two buck regulators, both LM2594s, one for +5 and one >>for -15. >> >>The TI LM2594MX-ADJ is about $1.40 in 100s, and there are zillions in >>stock. The ONsemi clone, LM2594D, is only 64 cents, but it looks like >>Digikey is the only distributor with any stock, and they have less than >>one reel. >> >>I like the medium-old bipolar switchers, because their nice slow edges >>make me less worried about switching junk getting into my low level >>circuitry. >> >>Any idea why the ONsemi ones are both cheap and apparently unpopular? >> >>Any suggestions for buck chips that will handle at least 40V and 0.5 A? >> >>Cheers >> >>Phil Hobbs > > Have you checked the ON Semi site? It could be that the LM2594 is being > discontinued. > > Use an LM339 and be safe ;-) > > Reminds me of a design of mine that produced both +5V and -12V... > > http://www.analog-innovations.com/SED/
OldStyleBuckSwitcherWithAddedNegativeOutput.pdf
> > What are the relative loads on your +5V and -15V? > > ...Jim Thompson
That is elegant to a cruel level. ?-))
On 20 Jul 2013 15:53:17 GMT, josephkk <joseph_barrett@sbcglobal.net>
wrote:

>On Fri, 19 Jul 2013 10:59:21 -0700, Jim Thompson wrote: > >> On Fri, 19 Jul 2013 13:47:06 -0400, Phil Hobbs >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >>>So we've got the +-40V sorted out, thanks to all. The next bit to >>>re-examine is the two buck regulators, both LM2594s, one for +5 and one >>>for -15. >>> >>>The TI LM2594MX-ADJ is about $1.40 in 100s, and there are zillions in >>>stock. The ONsemi clone, LM2594D, is only 64 cents, but it looks like >>>Digikey is the only distributor with any stock, and they have less than >>>one reel. >>> >>>I like the medium-old bipolar switchers, because their nice slow edges >>>make me less worried about switching junk getting into my low level >>>circuitry. >>> >>>Any idea why the ONsemi ones are both cheap and apparently unpopular? >>> >>>Any suggestions for buck chips that will handle at least 40V and 0.5 A? >>> >>>Cheers >>> >>>Phil Hobbs >> >> Have you checked the ON Semi site? It could be that the LM2594 is being >> discontinued. >> >> Use an LM339 and be safe ;-) >> >> Reminds me of a design of mine that produced both +5V and -12V... >> >> http://www.analog-innovations.com/SED/OldStyleBuckSwitcherWithAddedNegativeOutput.pdf >> >> What are the relative loads on your +5V and -15V? >> >> ...Jim Thompson > >That is elegant to a cruel level. > >?-))
Glad you liked it >:-} That design (actually using LM339's :-) is in several of the OmniComp/GenRad portable testers. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.