Cheapest switching regulator possible?

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Life of Brian
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Cheapest switching regulator possible?

Post by Life of Brian »

I need your input - what is the cheapest (lowest cost) switching regulator possible? I'd be using it for SNES portables, so probably just going from 7.5v to 5v with a load no more than 1A. The easiest way is to just use one of those switching regulators from Dimension Engineering, but at 15 bucks a pop it gets expensive if you build more than one portable at a time. Can anybody point me in the right direction?

Edit: Hey! I found a cheaper component that is absolutely identical to the Dimension Engineering one I just linked to. It's part #102-1715-ND at Digi-Key. It's only $10.80 as opposed to $15 so that's a step in the right direction. Anybody know of anything any cheaper?
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XCVG
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Re: Cheapest switching regulator possible?

Post by XCVG »

In the thread about getting 3.3V from 7805 there's some links. N64 section. Go there.
vskid
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Re: Cheapest switching regulator possible?

Post by vskid »

XCVG wrote:In the thread about getting 3.3V from 7805 there's some links. N64 section. Go there.
7805 is a linear regulator, inefficient (but cheap).

Get some samples from TI?
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Life of Brian
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Re: Cheapest switching regulator possible?

Post by Life of Brian »

vskid wrote:7805 is a linear regulator, inefficient (but cheap).
Exactly - inefficient. I'm planning on using a 3.5" AEI Comp screen with an SNES mini, and I want to run it off of six AA's with as much battery life as possible.

I'm researching this for portables to sell, so free samples aren't the way to go.
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jjhammerstein
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Re: Cheapest switching regulator possible?

Post by jjhammerstein »

How much does TI charge for those regulators?
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vskid
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Re: Cheapest switching regulator possible?

Post by vskid »

jjhammerstein wrote:How much does TI charge for those regulators?
I think the regulators are about $6 each from their distributors. It depends on the regulator, though. This is the one I'm talking about. Digikey seems to be on the expensive side for them.
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jjhammerstein
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Re: Cheapest switching regulator possible?

Post by jjhammerstein »

That's an option then.
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Kurt_
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Re: Cheapest switching regulator possible?

Post by Kurt_ »

You can *buy* as many samples as you want from TI, I think.
Hey, sup?
jjhammerstein
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Re: Cheapest switching regulator possible?

Post by jjhammerstein »

....Or buy them with money. He's trying to go legit, it seems.
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XCVG
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Re: Cheapest switching regulator possible?

Post by XCVG »

Hmmm, my post must not have gotten through.

I was saying that there are a few alternates in that thread. Also, I JUST found this:

http://www.sparkfun.com/commerce/produc ... cts_id=311" onclick="window.open(this.href);return false;

It's surface-mount, but someone like you could do it easy. Best of all it's only $6.

EDIT: I obviously can't read, because it says $7 and I quoted $6. Anyway you can get it in a TO-220 package from Digi-Key.
Basement_Modder
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Re: Cheapest switching regulator possible?

Post by Basement_Modder »

^I don't think he wants to go linear...
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Life of Brian
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Re: Cheapest switching regulator possible?

Post by Life of Brian »

I was researching the difference between switching regulators and low dropout regulators when I found this article. Very interesting read!

And, like Basement_Modder said, LDO's are linear, not switching.
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XCVG
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Re: Cheapest switching regulator possible?

Post by XCVG »

Basement_Modder wrote:^I don't think he wants to go linear...
Oh I'm dumb. I thought it was switching. I wish facepalm was a real smiley...
Life of Brian wrote:I was researching the difference between switching regulators and low dropout regulators when I found this article. Very interesting read!

And, like Basement_Modder said, LDO's are linear, not switching.
Read the above.

EDIT: clicky clicky!
Life of Brian
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Re: Cheapest switching regulator possible?

Post by Life of Brian »

XCVG wrote:EDIT: clicky clicky!
Good find, except I'm needing a 5v output, so something more like this.

Looking at the data sheet, I don't think I need a lot of what it suggests in the way of resistors and capacitors. I'm having difficulty determining what the bare minimum of components I would need for a portable.
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Re: Cheapest switching regulator possible?

Post by marshallh »

National's Simple Switcher series are about as easy as you can get. You do need all the components shown in the reference design, you'll get a lot of mysterious issues popping up if you try to skimp.

The efficiency is worth it though :D
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