LED driver LM3914 is there a smaller 8 pin 5 LED driver?

[Myron Samila]

Hi all,

I'm working on a little prototype, and I need to drive 5 LEDs instead of the 10 LEDs that
the LM3914/15 can drive.

Its more of a size thing I'm after, I need it to be as small as possible, or, maybe the
LM3914 comes in a SIP package? The 3914 has some interesting features that I need to
incorporate, and if I can find it in a SIP, that would probably solve most of my spacing
problems as I got to make this unit TINY (short of going all SMT, this is all through hole
stuff).

(I was originally planning to omit 5 of the outputs of the LM3914 anyhow, so I might still
go for that IF I can't find a substitute).

 

[CWatters]

You might be able to find a single chip micro in a very small package. Some
have A-D converters so it should be possible to program one of these to do
the same job as a 5 LED version of the LM3914.

Why not consider SMD? It's not impossible to hand assemble a mixed PCB at
home if that's the concern. In fact it can be easier to assemble SMD PCB
because there are fewer holes to drill. PCB layout is easier as well because
you can rune tracks right under components where there would normally be a
hole blocking the path.

 

[Myron Samila]

Hi,

Thanks for the reply. Actually, I found out that the LM3914 is available in a plastic
chip package, tiny little square. It must be installed into the appropriate socket, but
it certainly takes up less space. The LM3914 is a great IC, because it requires very
little to get the thing to do what you want.

What I think I'll end up doing (because of the low price of the 14-pin DIP IC version) is
just work around the size and make my PCB as small as possible. I think I can do it
somehow. Ahh, yes, SMT would be the way I'd like to go, however, I'm not getting them
silk screened or anything, or set up for wave solder. I'm just going to etch them myself
and tin them with solution. Should work

Thanks.

 

[CWatters]

Cheap PCB fab here....

http://www.pcb-pool.com/ppuk/info.html

 

[Myron Samila]

50 Euros for a tiny little PCB is not cheap.

I can make a 2" x 3" PCB in a small quantity single sided and drilled for $3/unit
Canadian!! All this internet PCB manufacturing is hilarious. I went to an electronics
show here in Toronto where there were no less than 10 PCB manufacturers displaying their
product, I was very impressed that all of them would do small production runs (very small
includes 2-50 pieces of any size).

Basically, I intend on doing them myself. If I use surplus single sided board, my own
etching solution, photo resist, and tinning, I don't mind drilling. I've got the
equipment, and certainly have the time, so I think I can make my PCBs fall in at an
amazing price

I just need to find software to draw the thing out so I can print it. I found one nice
utility, free trial download, BUT, it didn't include an Undo feature, and it had every
trace layout available except LEDs! I tried arranging IC spacing to accomodate a standard
1/4" LED, and it didn't work.

In the old days, I just just use to draw it all on paper using Radio Shack IC rub on
transfers, and draw the traces with marker. Then make a negative out of it. I guess I
still could do that, scan it, and laser print it to transparency.

 

[[email protected]]

50 Euros for a tiny little PCB is not cheap.

I can make a 2" x 3" PCB in a small quantity single sided and drilled for $3/unit
Canadian!! All this internet PCB manufacturing is hilarious. I went to an electronics
show here in Toronto where there were no less than 10 PCB manufacturers displaying their
product, I was very impressed that all of them would do small production runs (very small
includes 2-50 pieces of any size).

What show was that? I'm new to electronics and I would have liked to
go to that show to see the PCB manufacturers. When does the show run?

 

[CWatters]

50 Euros for a tiny little PCB is not cheap.

Not bad for a single euro board double sided PTH. If your boards are smaller
you can do step and repeat to fit several in that area.

I can make a 2" x 3" PCB in a small quantity single sided and drilled for $3/unit
Canadian!! All this internet PCB manufacturing is hilarious. I went to an electronics
show here in Toronto where there were no less than 10 PCB manufacturers displaying their
product, I was very impressed that all of them would do small production runs (very small
includes 2-50 pieces of any size).

Basically, I intend on doing them myself. If I use surplus single sided board, my own
etching solution, photo resist, and tinning, I don't mind drilling. I've got the
equipment, and certainly have the time, so I think I can make my PCBs fall in at an
amazing price

I guess I'm used to doing slightly more complex boards that I simply
wouldn't attempt to make myself - I also have twin twin boys age 2 which
might have something to do with it .

I just need to find software to draw the thing out so I can print it. I found one nice
utility, free trial download, BUT, it didn't include an Undo feature, and it had every
trace layout available except LEDs! I tried arranging IC spacing to accomodate a standard
1/4" LED, and it didn't work.

Perhaps you could use the foorprint for a 2 pin 0.1" pitch header (eg
Molex)?

In the old days, I just just use to draw it all on paper using Radio Shack IC rub on
transfers, and draw the traces with marker. Then make a negative out of it. I guess I
still could do that, scan it, and laser print it to transparency.

The free version of Target 3001 from http://www.pcb-pool.com/ppuk/info.html
has all the library parts you need but it won't print out artwork at 100%
scale (to force you to use their PCB service) HOWEVER there is an obvious
trick you can use to get 100% artwork. Details by email if anyone really
can't work it out.

 

[Watson A.Name - Watt Sun, Dark Remover]

Hi all,

I'm working on a little prototype, and I need to drive 5 LEDs instead of the 10 LEDs that
the LM3914/15 can drive.

Its more of a size thing I'm after, I need it to be as small as possible, or, maybe the
LM3914 comes in a SIP package? The 3914 has some interesting features that I need to
incorporate, and if I can find it in a SIP, that would probably solve most of my spacing
problems as I got to make this unit TINY (short of going all SMT, this is all through hole
stuff).

(I was originally planning to omit 5 of the outputs of the LM3914 anyhow, so I might still
go for that IF I can't find a substitute).

You gave no information on the type of LED, voltage, etc.


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[Myron Samila]

Umm, LM3914 drives all LEDs, period. It can also drive low current lamps, such as the
7912. That is why I didn't need to give any info on the LED specification. It is
irrelevant.


The LM3914 LED driver is probably the most popular one of its kind. Voltage makes no
matter either, the LM3914 can run from anywhere from 3V up to 28V and you can vary the
LEDs brightness by simply using one resistor on one pin of the IC (Mode function).
Current stability of the LM3914 is also excellent.

BTW: I've already found the solution, square package IC, its very small. Same IC, just
takes up less space. It however must snap into a socket, whereas the LM3914 is a DIP.

 

[Myron Samila]

Yes, PTH can get pricey. I'd imagine that it would get quite a bit more expensive if I
wanted to have it screened and such, but since I'm assembling these units, I think I can
manage

Thanks for the link on the utility, I'm going to try that out. hehe, and the 100% scale
thing, I've got a few ideas . But, if the software is actually great, does everything I
need, I'll see if they can actually sell a functioning copy, orrrrrr..... have them make
a PCB for me.

 

[Myron Samila]

Hi there Weblurker,

The show is in Markham Ontario (just outside of Toronto). Its not a huge show, but it is
a great show for technicians, designers and such to get some info on various equipment and
products.

It is held by a magazine called EP&T, (Electronic Products and Technology). This magazine
is free to people in the electronics industry. I don't have a website handy, but if you
do a goolge search, you will find the info. I think the show was in February, so if you
are local, (actually, the show tours most of Canada). It is a small show, but, hey, I
found some interesting test equipment there and also found some inexpensive PCB
manufacturing companies there that will do prototypes.

Hope that helps. And thank you to everyone who responded to my post. I've found my
solution!!!

Now on to solving the next problems!!hahah

 

[CWatters]

Yes, PTH can get pricey. I'd imagine that it would get quite a bit more expensive if I
wanted to have it screened and such, but since I'm assembling these units, I think I can
manage

Thanks for the link on the utility, I'm going to try that out. hehe, and the 100% scale
thing, I've got a few ideas . But, if the software is actually great, does everything I
need, I'll see if they can actually sell a functioning copy, orrrrrr..... have them make
a PCB for me.

Yes you can get an upgrade from the makers of Target 3001, The open version
allows you to make Gerber files for fab anywhere.

One point though.. I had a problem using the PCB Pool service first time.
It seems my ISP blocks port 25(?) which their S/W uses to send the data to
PCB Pool by email (some kind of anti spam measure). I had to get the program
authors to send it for me which they did. Expect new version soon that
allows you to enter your own SMTP server or similar fix..

Overall I like Target 3001 very much. It's very easy to create new library
symbols and foot prints.

 

[[email protected]]

Hi there Weblurker,

The show is in Markham Ontario (just outside of Toronto). Its not a huge show, but it is
a great show for technicians, designers and such to get some info on various equipment and
products.

It is held by a magazine called EP&T, (Electronic Products and Technology). This magazine
is free to people in the electronics industry. I don't have a website handy, but if you
do a goolge search, you will find the info. I think the show was in February, so if you
are local, (actually, the show tours most of Canada). It is a small show, but, hey, I
found some interesting test equipment there and also found some inexpensive PCB
manufacturing companies there that will do prototypes.

Thanks for the reply. I did the google search and found this url:

http://www.ept.ca/docs/index.php?PageName=main

The next show will be in Thornhill in April 2004.

http://www2.ept.ca/eptech.html

 

[cpemma]

Hi all,

I'm working on a little prototype, and I need to drive 5 LEDs instead of the 10 LEDs that
the LM3914/15 can drive.

I see you're sorted now, but for reference Sanyo do a 5-led 9-pin SIL,
LB1443N, but it's a vu-meter (dB) scaling as 3916.

Also a 12-led vu-meter chip, LB1412.

 

[Myron Samila]

Now that is EXACTLY what I was looking for. nice and simple too!!

However, hard to find here in Canada!! I've been searching for a while, I got the tech
docs though.

One feature it doesn't have is that you can't make the display flash when all 5 leds are
lit, the LM3914 does (if you select that mode). But, if the price is right on that Sanyo
IC, I'll use it!! The LM3914 typically sells for $5.00/unit Canadian from DigiKey (about
$4.27 actually in low quantities).

Thanks!

 

[cpemma]

Now that is EXACTLY what I was looking for. nice and simple too!!

However, hard to find here in Canada!! I've been searching for a
while, I got the tech docs though.

One feature it doesn't have is that you can't make the display flash
when all 5 leds are lit, the LM3914 does (if you select that mode).
But, if the price is right on that Sanyo IC, I'll use it!! The
LM3914 typically sells for $5.00/unit Canadian from DigiKey (about
$4.27 actually in low quantities).

For comparison, my catalogue (Rapid Electronics here in the UK) has the
LM3914/5/6 @ £2.10 each (£1.20/100 off), LB1443N @ £0.70 each (£0.46/100)

 

[CWatters]

One feature it doesn't have is that you can't make the display flash when all 5 leds are
lit,

It's basically an analog device so it might be possible to connect the 5th
LED back to the input somehow to make it oscillate when the 5th LED lights
up?