3 cent blinky what else can it do?

[westfw]

LM3909  Another useful chip that TI decided to kill off

The LM3909 was discontinued long before TI acquired National Semi?  (I can find posts describing it as "long out of production" in 2003; the TI acquisition was in 2011...)
It was more-or-less rendered obsolete by advances in LEDs, Batteries, low-voltage low-power circuitry, and boost-mode voltage regulation anyway.

[rrinker]

 Yeah, once they started selling LEDs with the blinky circuit already embedded in them, it was all but over for a dedicated 8 pin PDIP like the LM3909.

[coppice]

LM3909  Another useful chip that TI decided to kill off

The LM3909 was discontinued long before TI acquired National Semi?  (I can find posts describing it as "long out of production" in 2003; the TI acquisition was in 2011...)
It was more-or-less rendered obsolete by advances in LEDs, Batteries, low-voltage low-power circuitry, and boost-mode voltage regulation anyway.

There are only 3 reasons a chip goes obsolete at most vendors:

• It has been truly superceded by a drop in replacement.
• They are only selling a handful of parts, and it is unrealistic to keep the part listed.
• The only fab which can make it is closing, and the cost of re-engineering it for another fab is prohibitive for the market size.

All 3 possibilities mean very few customers are seriously affected. Those who are affected are typically handled through lifetime buy notices from the vendor before the part is dropped, and one of the specialist long term support companies who hold die banks or stocks of completed parts in controlled conditions that minimise degradation. Those guys are pricey, though. A lifetime buy is normally a far better choice for the customer.

[james_s]

I never really got the excitement over the LM3909. I had one when they were newish, it was interesting to play with but it's not *that* remarkable to be able to blink an LED off a single cell. Yes it can be used for a bunch of other hacks but none of those projects jump out at me as being terribly useful. When designed it was envisioned that it would be built into millions of flashlights to make them easier to find in the dark but that never really happened. I think the only commercial project I've ever seen one in was the box of a Pink Floyd album and that's hardly the sort of volume that will keep an IC in production.

[chris_leyson]

The Lm3909 had extremely low operating current

[james_s]

Yes but so what? What was really a good volume use case for it? What commercial products have you seen that used it? Is there really a big value in having a blinking light on every flashlight? To sustain a specialized IC like that, it needs to have multiple high volume uses.

[westfw]

The LM3909 was not a cheap IC, nor was the the supporting circuitry (it needed a "big" capacitor.)
On top of that, it produced really wimpy flashes (you know: discharging a 300uF through the LED, essentially.)Anyone who wanted a blink LED found it cheaper and better to just add a second battery cell, or use a lithium cell.

It was sort-of neat, but a Joule Thief is neater.  (Is there a flashing Joule Thief?)
(There have been some interesting circuits posted of semi-conventional microcontroller circuits that drive their own step-up converter to allow them to run off a single cell, after an initial button-press provides the first pulse of high-enough voltage.  These days you can get microcontrollers with built-in boost regulators and/or very low-voltage operation, so a primitive circuit that does little more than flash an LED isn't all that interesting.  (although the people who think that a 555 can "do the same thing" as a 3909 are missing the point...)

[Fungus]

It was sort-of neat, but a Joule Thief is neater.  (Is there a flashing Joule Thief?)

All joule thieves flash. 

[Beamin]

Seriously, you need to sit down talk seriously with your boy friend about his TLC for you, feel sorry & pity. 

 

I didn't realize it was a micro from the title.

It has Micro in the title and description. And I've done two previous videos with "micro" in the title and description.

[Beamin]

Seriously, you need to sit down talk seriously with your boy friend about his TLC for you, feel sorry & pity. 

 

I didn't realize it was a micro from the title.

It has Micro in the title and description. And I've done two previous videos with "micro" in the title and description.

Yes but I think I have been on this board long enough to for you guys to know that saying something 3 times in the title and multiple videos and … I still don't get it. 

One day I may even figure out this e=IR Einstein equation nonsense, or that Roy G. Biv guy they keep talking about. Who is roy did he invent the resistor? Also what value of resistor can be substituted for a capacitor? 47 instead of 50? Looks like I'm 3 electrons short of a full deck.

[drussell]

Looks like I'm 3 electrons short of a full deck.

Indeed.

[Fungus]

Looks like I'm 3 electrons short of a full deck.

Indeed.

"Deck"?

Maybe it could be: "3 electrons short of a full charge".

[Beamin]

Looks like I'm 3 electrons short of a full deck.

Indeed.

"Deck"?

Maybe it could be: "3 electrons short of a full charge".

Its an American expression. Your flag in your profile is a black X so I don't know what language you speak...

[Fungus]

"Deck"?

Maybe it could be: "3 electrons short of a full charge".

Its an American expression. Your flag in your profile is a black X so I don't know what language you speak...

I believe "deck" usually refers to playing cards in the USA, which don't have electrons.

I'm just trying to make an EE version of the expression, how about "3 electrons short of a joule"?