MC34063 with small inductors
in [Design]
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From: Joerg on 6 Apr 2010 21:00 Hello Folks, Have to correct a design with a 34063 in there. Buck, VIN 16-30V, VOUT slightly under 12V, 400mA max output. And no, I don't like it much :-) One of the issues is a saturating inductor. Can't change the layout and to be able to cram one in there I probably have to drop down to 47uH, maybe 68uH if lucky. SPICE says it's ok but none of the datasheets or app notes recommends going that low. Any reason why not? -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jim Thompson on 6 Apr 2010 21:10 On Tue, 06 Apr 2010 18:00:41 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Hello Folks, > >Have to correct a design with a 34063 in there. Buck, VIN 16-30V, VOUT >slightly under 12V, 400mA max output. And no, I don't like it much :-) > >One of the issues is a saturating inductor. Can't change the layout and >to be able to cram one in there I probably have to drop down to 47uH, >maybe 68uH if lucky. > >SPICE says it's ok but none of the datasheets or app notes recommends >going that low. Any reason why not? Just stick a CD4060 in there. That oughta fix it ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: brent on 6 Apr 2010 21:12 On Apr 6, 9:10 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- Web-Site.com> wrote: > On Tue, 06 Apr 2010 18:00:41 -0700, Joerg <inva...(a)invalid.invalid> > wrote: > > >Hello Folks, > > >Have to correct a design with a 34063 in there. Buck, VIN 16-30V, VOUT > >slightly under 12V, 400mA max output. And no, I don't like it much :-) > > >One of the issues is a saturating inductor. Can't change the layout and > >to be able to cram one in there I probably have to drop down to 47uH, > >maybe 68uH if lucky. > > >SPICE says it's ok but none of the datasheets or app notes recommends > >going that low. Any reason why not? > > Just stick a CD4060 in there. That oughta fix it ;-) > > ...Jim Thompson > -- > | James E.Thompson, CTO | mens | > | Analog Innovations, Inc. | et | > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | > | Phoenix, Arizona 85048 Skype: Contacts Only | | > | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | > | E-mail Icon athttp://www.analog-innovations.com| 1962 | > > The only thing bipartisan in this country is hypocrisy Won't a 555 do the trick?
From: tm on 6 Apr 2010 21:23 "brent" <bulegoge(a)columbus.rr.com> wrote in message news:91110477-cc99-4dc0-844c-e4322b214131(a)n13g2000vbn.googlegroups.com... On Apr 6, 9:10 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- Web-Site.com> wrote: > On Tue, 06 Apr 2010 18:00:41 -0700, Joerg <inva...(a)invalid.invalid> > wrote: > > >Hello Folks, > > >Have to correct a design with a 34063 in there. Buck, VIN 16-30V, VOUT > >slightly under 12V, 400mA max output. And no, I don't like it much :-) > > >One of the issues is a saturating inductor. Can't change the layout and > >to be able to cram one in there I probably have to drop down to 47uH, > >maybe 68uH if lucky. > > >SPICE says it's ok but none of the datasheets or app notes recommends > >going that low. Any reason why not? > > Just stick a CD4060 in there. That oughta fix it ;-) > > ...Jim Thompson > -- > | James E.Thompson, CTO | mens | > | Analog Innovations, Inc. | et | > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | > | Phoenix, Arizona 85048 Skype: Contacts Only | | > | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | > | E-mail Icon athttp://www.analog-innovations.com| 1962 | > > The only thing bipartisan in this country is hypocrisy Won't a 555 do the trick? I think it needs an ideal diode. :)
From: Jim Thompson on 6 Apr 2010 21:22
On Tue, 6 Apr 2010 18:12:49 -0700 (PDT), brent <bulegoge(a)columbus.rr.com> wrote: >On Apr 6, 9:10�pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- >Web-Site.com> wrote: >> On Tue, 06 Apr 2010 18:00:41 -0700, Joerg <inva...(a)invalid.invalid> >> wrote: >> >> >Hello Folks, >> >> >Have to correct a design with a 34063 in there. Buck, VIN 16-30V, VOUT >> >slightly under 12V, 400mA max output. And no, I don't like it much :-) >> >> >One of the issues is a saturating inductor. Can't change the layout and >> >to be able to cram one in there I probably have to drop down to 47uH, >> >maybe 68uH if lucky. >> >> >SPICE says it's ok but none of the datasheets or app notes recommends >> >going that low. Any reason why not? >> >> Just stick a CD4060 in there. �That oughta fix it ;-) >> >> � � � � � � � � � � � � � � � � � � � � ...Jim Thompson [snip] >Won't a 555 do the trick? Even better !-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy |