From: Justin Richards <justin.richards@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Sun, 12 Sep 2021 23:13:21 -0700
Subject: Re: [EE] LM1084 regulator question
Thread-Topic: [EE] LM1084 regulator question
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Hi Bill,

if you are looking for cheap, I use  something like "Mini360 3A DC-DC
Voltage Step Down Converter Buck 4.75-23V to 1-17V" fom ebay for ~$3

Not sure they are good for the rated 3A, but if this is something you would
consider using i would be happy to load one up and see which point it fails=
..

Justin

On Mon, Sep 13, 2021 at 12:54 PM William Couture <bcouture@gmail.com> wrote=
:

> As a reply to everyone:
>
> The output capacitor is a 22uF electrolytic, thought it would be enough.
>
> But, from the other comments, it's a thermal problem -- too much power
> (heat)
> is being dissipated going from 24V (needed elsewhere in the system) to 5V=
..
>
> I'll look at switching supplies and see what I can do there.
>
> Thanks!
>    Bill
>
> On Sun, Sep 12, 2021 at 10:33 AM William Couture <bcouture@gmail.com>
> wrote:
>
> > Hi!
> >
> > I need about 3A of 5V, with a 24V supply.  I'm trying to use a LM1084 i=
n
> a
> > TO-220, which is
> > rated at 5A output.
> >
> > However, when I try to pull more than about 250mA, the regulator become=
s
> > very hot and I
> > start getting dropouts.  A heatsink does not help.
> >
> > I have an electrolytic capacitor on the output, not a tantalum like in
> the
> > datasheet, could that
> > be the problem?
> >
> > I tried putting a 7805 in the circuit (with appropriate pinout changes)
> > and it's fine up to 1A,
> > so the problem is the LM1084 itself.
> >
> > If the LM1084 will not work, can anyone suggest a low-cost circuit to g=
et
> > 3A or so of 5V
> > from 24V?
> >
> > Thanks,
> >    Bill
> >
> > --
> > Psst...  Hey, you... Buddy...  Want a kitten?
> straycatblues.petfinder.org
> >
>
>
> --
> Psst...  Hey, you... Buddy...  Want a kitten?  straycatblues.petfinder.or=
g
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