Replacement Chip
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Stampers
A friend of mind is looking for a LED driver chip replacement.· He was looking for a LM3909 single chip LED·driver.· Evidently the chip is no longer available and now he is trying to find a replacement.· His application is a small powered device with a flashing LED for fishing.· Any ideas?· I told him that I would present the question to the forum.
Thanks
Brian McMillion
A friend of mind is looking for a LED driver chip replacement.· He was looking for a LM3909 single chip LED·driver.· Evidently the chip is no longer available and now he is trying to find a replacement.· His application is a small powered device with a flashing LED for fishing.· Any ideas?· I told him that I would present the question to the forum.
Thanks
Brian McMillion
Comments
The LM3909 is still available, at about $5.00 each, you can get all
you want. I suggest you try findchips.com. Plug in a part number and
23 (or so) vendors will be queried as to availability. Now, on to
your problem.
The 3909 is a wonderful little device. (pardon any errors, I'm
working from memory) Advantages are few components, low power
consumption (a handful of microapms) and the ability to operate from
a single 1.5 volt power source. The disadvantages: cost and
availability.
If you really need to operate from a single 1.5 volt cell additional
components will be required to double the 1.5 volts, allowing 3 volt
logic to be used. It is possible to accomplish this in a way that is
even more efficient that the 3909, but you're talking a bunch of
parts.
You could use a 5 volt blinking LED, you could wire up 2 inverters as
an oscillator, use another inverter as a buffer, and be good to go.
(A hex inverter IC has 6 inverters in it. Cheap and easy.)
You could use a 555 (my favorite) to get the job done. A 555 will
source or sink 200mA, very robust. Using the 555 you can tailor the
duty cycle so the led only blinks briefly. Doing this will increase
battery life. I have made a LED blink this way for days using a
partially discharged 9 volt battery.
Radioshack.com has a few led blinker ic's. I have not looked at them,
maybe one of those will be best for you.
We all miss the 3909. It is a great little chip.
Good Luck
Rich http://geocities.com/rbc1956
--- In basicstamps@y..., "Brian & Sandy McMillion" <brianmcm@w...>
wrote:
> Stampers
> A friend of mind is looking for a LED driver chip replacement. He
was looking for a LM3909 single chip LED driver. Evidently the chip
is no longer available and now he is trying to find a replacement.
His application is a small powered device with a flashing LED for
fishing. Any ideas? I told him that I would present the question to
the forum.
> Thanks
> Brian McMillion