Sun Buzz 9v to 1.5 volt, LM317?

[rockgardenlove]

So, I have my Sun Buzz all set up.  I got some LM317s from another member, no T suffix, so these are the small little standard black plastic transistor cases that I forgot the name of.  TO-92?
Anyways, will they work in this standard application for my purposes?
http://www.national.com/images/pf/LM317/00906301.pdf

Thanks!

[rockgardenlove]

Wish you could edit...
I just noticed that in the datasheet it doesn't say that the LM317 even comes in that package.  What's up with this?  Are my little transistor-shaped LM317s even power regulators at all?

[Paul Perry (Frostwave)]

http://www.national.com/pf/LM/LM317.html

"adjustable output down to 1.2V".
So yeah, go for it mate!
And if it has LM317 on it, then yes it is a reg whatever case it is in.

[rockgardenlove]

Alright then, cool, thanks!
One other thing though, what's the pinout for the little case?  Same as the big one?

Thanks!

[sfx1999]

Maybe it is this one -> http://www.onsemi.com/PowerSolutions/product.do?id=LM317L

[gez]

One other thing though, what's the pinout for the little case?  Same as the big one?

Look for a little logo on the device (you might need a magnifying glass and they're not always there, but you never know).  Once you've sussed who makes it, go to their website and check their data sheet.  If you don't recognise the logo, get into the habit of clocking them whenever you look at data sheets, you'll soon learn to recognise the main ones (this will help you for future occasions).

[rockgardenlove]

There's a Motorola on there, I looked yesterday for the Motorola datasheet, but didn't find anything.  Granted, that was 4 AM (so I guess it was today, heh), but I didn't find anything.

It says LM317LZK8703.  I found it on that link you sent SFX1999, thanks.  It's the LM317LZ, which seems obvious now.

Thanks!

[rockgardenlove]

Could somebody help me with the calculation of my resistor values?
Here's the formula:

Vout=1.25V (1+R2/R1)+Iadj R2

So, I'm solving for R1 and R2...right?  I can do that, if I know what the Iadj is supposed to be.  What should it be?  No idea what to plug in for Iadj.

Thanks!

I found that datasheet...application on first page:
http://www.ortodoxism.ro/datasheets/motorola/LM317LBD.pdf

[sfx1999]

Iadj is the current that passes through the middle terminal of the regulator. It says it is irrelevant in most applications because it is so small.

R1 is given as 240, so:

R2 = 240*(V/1.25 - 1)

So, for 1.5V, I get 48 ohms. This seems like a very inefficient way to do this. A zener and resistor combination would probably be better.

[rockgardenlove]

Yeah, it does seem somewhat inefficient, but I don't have a Zener handy.  This should work, though, thanks!

[petemoore]

  I dunno, so I'd keep a finger on it for heat dissipation, that's a big drop, if it heats up alot I'd consider...taking it easy or having a spare or something different.

[rockgardenlove]

Yeah, it does seem somewhat inefficient, but I don't have a Zener handy.  This seems to work fine.  I epoxied it right up against the wall of my box, so it should be ok heat wise.

Thanks very much!  Here's how it turned out:

[jaytee]

what's a sun buzz? A fuzz face type thing? What's the 1.5v for?

[rockgardenlove]

http://www.diystompboxes.com/smfforum/index.php?topic=56742.0
Here's where I got the schem, etc.  It's basically just transistor gainstages that overdrive, so yeah, you could say Fuzz Facish I suppose.  It's much more aggressive sounding though, probably due in part to the silicon transistors.  Also it's got a really small output cap that isn't FFish.

[Paul Perry (Frostwave)]

Adding a pot to the LM317 regulator to crank the voltage up & down, might be useful. Anyone tries this (or just hangs the Buzz off a variable power supply to check it out) please let us know!

[rockgardenlove]

I'd do it, except I have no room inside my box.  The box layout is really awkward as is...I originally drilled the box out for a no-knobber.

I do know that it doesn't work at 9v though!