[DaKi][er]

Last night I was bored and thought of the idea of putting a Jung based regulator on something pin compatible that would fit right onto an existing LM78XX regulator, and loaded up Eagle layout editor and after playing around a bit found out that you can squeeze quite a lot onto something very small

After thinking I’d done such a good job I thought I would share it with everyone else here, so here it is

Schematic

I know how much everyone here loves smd

but it's not like you got any choice trying to fit everything onto something only 0.480 * 1.110 inches big and I did at least keep everything to 1206 sizes but the zener on the output of the opamp I couldn’t fit in the bypass capacitor anywhere so they get stacked one on top of the other on the one pad

(Also on the schematic, the LM329DZ symbol is meant to be a zener diode but because i couldn’t be bothered to make one up so i borrowed it from a transistor

Star ground wiring just fell into place and ultra short signal paths should keep this potentially wild circuit tame though actually building one and testing is probably needed

A negative regulator could be made up in the same way for pin compatible with LM79XX

 

[Nisbeth]

Great idea!

FYI Tangent has an eagle-library with the LM329 in it

http://www.tangentsoft.net/elec/parts/eagle/


/U.

 

[motherone]

Nice boards! I bet you could arrange a very successful group buy around them

 

[Garbz]

i think what motherone was trying to hint at was that you should arrange a very successful group buy around them

 

[rellik]

thats if you could....


EDIT: on head-fi that is

 

[DaKi][er]

I don’t want to organise a group buy and I think we've seen enough of them here as is, but, I’ll post up Gerber files for anyone to have them made
www.sparkfun.com have a pcb service for US$5 in^2. and that would make them only $5 each in single quantities which is pretty good and after you've placed an order with them the first time the second order they drop the price down to $2.50

I'll probably do up one or 2 sometime later to see how it goes, but if anyone wants to go before me, please go ahead

 

[peranders]

Looks good but don't underestimate potential troubles meaning prototyping is very important. This is a wideband design and with that unexpected problems. As a first look it's looks alright but I haven't check every part and their placement.

Have you seen this:
http://www.diyaudio.com/forums/attac...amp=1083062649
http://www.diyaudio.com/forums/attac...amp=1052933201

 

[peranders]

Quote:

Originally Posted by motherone Nice boards! I bet you could arrange a very successful group buy around them

Notice that group buys are banned here at the moment.

Projects with SMD parts are doomed to be unsuccessful, to hard to build for most people, I know what I'm talking about but I like SMD also.

 

[DaKi][er]

Hey peranders, I was wondering when you were going to chime in here

I think I do remember those reg’s actually, or something similar

I'm a big fan of SMD as well, and I know how anti smd most people are here but i know they'll eventually budge if we keep pushing it, most of it is fear and no experience that is stopping people

I’ve found a few small errors going over it already, the 2n5087 had 2 of the pads around the wrong way that was an easy fix and also one of the vias was shorting to a pad that it shouldn’t have been

I need to make a digikey order sometime in the next month so I’ll probably add the few extras needed for this in and get a pcb whipped up

Attached are the Gerber files that should be exactly how sparkfun.com wants them if anyone wants some made

 

[peranders]

The pcb of yours might work, surely after some tweaks. If you are planning to make pcb's with plated holes I recommend you to have round pads for every holemounted part in order to save valuable space. Suitable pad for TO220 is 75 mils in the normal case but in your case you can shrink it to 63 mils.

 

[robzy]

Ohh... that is very interseting! Jung super regulators are meant to be... super... arent they?

I would be interested in a couple of boards. (It would be great if they were a "dropinish" replacement for the 317 too )

Rob.

 

[skyskraper]

its just as easy to have it as a drop in for the 78XX regs.

 

[mekanoplastik]

how much current can a/this jung regulator deliver?

 

[peranders]

Made like this it's about 100 mA or so. A Jung regulator in general, lot's of amperes if it's made right but the preregulator (if you use one) sets a limit, 1.5 A with LM317.

 

[DaKi][er]

With some heatsinking of the lm317 on it and making sure there isn’t a big voltage drop over it (5-6v being ideal) I was estimating around 200mA max

Also note, it’s got a minimum voltage of 10v to keep the ad825 opamp on it happy, you can go lower if you use a suitable opamp that will run at a lower voltage but then you'll hit the limit of the reference voltage of 6.8v of the LM329DZ