LM4702 info

[ahrsix]

I am a new member of this great club, this is my first posting and I am sure to get it wrong, but here goes! I would like to make my wife a 200watt amp, I have got the LM4702 in mind, and I make a good PCB (no words and music) I have a 500va 50v 0v 50v toroidal transformer and most other things I think I’ll need, “all” I need now is some kind person to help, in short a schematic or ideally a print out of the PCB, Power Supply, an overlay of the components and of course a component list.
I feel sure some one has put this info on this site previously I have been looking for three days but most of it’s over my head. Any help would be deeply appreciated.
Ahrsix.

[Netlist]

Welcome Ahrsix
Here perhaps? And here

/Hugo

[lgreen]

I haven't seen any of those around here. But sounds like a fun project.

why don't you start with the application note? There is a full board layout schematic and parts list and how to guide at National Semiconductor's LM4702 page-
here.

[Mark St. Denis]

Hi,

Come over to the pre-existent LM4702 threads (2 or more at this

time).

Your welcome anytime. Start a new thread? What topics?

Please be specific in you topic, for the fun of it.

Peace

Mark

[Mark St. Denis]

Hi,

There is a group of very good people on LM4702 studies.

Look at pre-existent threads.

It may seem hyper-technical to some, yet the people I have met are always willing to give novice advice, since I am a beginner myself.

The LM4702 threads are full of friendly people. Ask any question you want. Post any theory or practice that you want. You are welcome.

Mark

[elementx]

I find that the best place to find information on National brand chips... is the official National PDF document!

goto National.com, type in lm4702 and look at there schematics. I just purchased a dozen LM4702 boards form the user "VETERAN", and they look great. I'll be building them soon. Maybe you can see if he has anymore boards.

[Mark St. Denis]

Hi Buddy,

G1 who and G2 who feel circuits differently, is that pure

electronics philosophy?

Call back anytime, but do not get me in trouble with the

moderators, because I am the conservative typo-erer.

Mark

[Mark St. Denis]

Hi

I read your post more carefully. You want PCBs. Both members (1) dfdye and (2) veteran have completed PCBS available.

The easy way to navigate the site, is to go to the home page of DIYAUDIO and click on the SEARCH icon and use the search term LM4702.

This will then show all LM4702 treads (including your new one) and show the group buy treads for the 2 available PCBs.

You said you wanted 200 watts per channel. This is a topic on the threads right now, because most people are working with lower 100-125 watt prototype boards, designing and testing different output stages.

I hope this post answers your questions specifically and accurately.

If you need any help, just email me or post me, yet I am no electronics wizard.

Mark

[ahrsix]

Many thanks for all you replies. I have followed your advice and found it very helpful, having looked at the “Application information” at www.national.com, I do not like there circuit, I try never to put tracks (you may call them Traces) between chip legs it’s just a thing I don’t do, and the pads are a bit tiny to drill. But it does give me some thing to work from. I may try buying a board or two, the snag is you only see group buys in America, and I wanted them for my wife’s birthday, I don’t think they would arrive on time. Thanks again guys.
Ahrsix.

[dfdye]

Originally posted by ahrsix
I try never to put tracks (you may call them Traces) between chip legs it’s just a thing I don’t do, and the pads are a bit tiny to drill. But it does give me some thing to work from.

Are you talking about etching your own boards? If so I absolutely understand the reluctance to use tiny traces, but if you are having them done professionally, there is more than enough space to get the traces between pads.

David

PS to save you sifting through a ton of random threads, here is the most developed thread of the bunch. Incidentally, as I am sure you have seen, National put out a nice application note in addition to the note about the chip. You can probably get as much from reading this note as reading any of the threads on the board since we are all still tinkering with our individual designs.