LM3909 replacement with low power consumption

[Brooke Clarke]

Hi:

Since the LM3909 flasher chip is long out of production is there a
replacement chip or circuit that has the same or lower power consumption
(assuming the same LED was used on both)?
I did find a web page that implemented the schematic from the LM3909
using discrete components. Is this the lowest power consumption approach?

Thanks,

Brooke Clarke, N6GCE

 

[Spehro Pefhany]

Hi:

Since the LM3909 flasher chip is long out of production is there a
replacement chip or circuit that has the same or lower power consumption
(assuming the same LED was used on both)?
I did find a web page that implemented the schematic from the LM3909
using discrete components. Is this the lowest power consumption approach?

Looks easy enough- all the values are given on the schematic. Just
have to replace that mutant dual-collector transistor with two
discretes with emitter-ballast resistors. Probably fit it on a PCB not
much bigger than a DIP-8. ;-)

Best regards,
Spehro Pefhany

 

[Rolavine]

From: Brooke Clarke [email protected]

Since the LM3909 flasher chip is long out of production is there a
replacement chip or circuit that has the same or lower power consumption

There is so much talk of this chip maybe someone should bring it back to life,
I can't believe it was hard to make?

 

[S. Pefhany]

There is so much talk of this chip maybe someone should bring it back to life,
I can't believe it was hard to make?

Probably more of a market size thing. It won't work on a blue LED either.
There are more power-hungry (3V and more current) chips that do a similar
thing for very cheap (no electrolytic cap) available. See, for example, the
flasher on some (Logitek?) mouse boxes.

SP

 

[Jim Thompson]

Probably more of a market size thing. It won't work on a blue LED either.
There are more power-hungry (3V and more current) chips that do a similar
thing for very cheap (no electrolytic cap) available. See, for example, the
flasher on some (Logitek?) mouse boxes.

SP

The LM3909, originally called "The Miser", was designed by fellow MIT
class of 1962 grad Robert A. Hirschfeld back in the '60's.

Then he went on to become a lawyer, espoused father's rights in child
custody cases, and was ultimately disbarred here in Arizona a few
years ago ;-)

One of my own lawyers is married to Hirschfeld's daughter.

John F. Banzhaf III was also an EE graduate of the class of 1962.
He's now the lawyer behind all the suits against junk food. Gives you
an idea what a weird graduating class that was ;-)

Back to the LM3909...

The data sheet schematic is a reasonably good representation of the
actual circuit... seems you young bucks might copy it as a discrete
circuit and embellish it for blue LEDs.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| Jim-T@analog_innovations.com Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

For proper E-mail replies SWAP "-" and "_"

Why is it that Democrats can't debate politely?
And are only rude and interruptive.
Lack of mental capacity?

 

[Ben Bradley]

Back to the LM3909...

The data sheet schematic is a reasonably good representation of the
actual circuit... seems you young bucks might copy it as a discrete
circuit and embellish it for blue LEDs.

I recall seeing several brands of microcontrollers available in
8-pin packages, or other packages about the same size as an 8-pin DIP
(fully self-contained, flash-programmable, internal R-C oscillator)
that could be easily programmable as a "LED flasher", perhaps even
with flash speed controlled an external capacitor. Perhaps the best
for low current consumption would be the MSP430.
These are less than a dollar each. What did the LM3909 cost?
One possible problem is these things work at lower and lower
voltages, perhaps too low to light a blue LED.
How would this compare with a 555, either bipolar or CMOS version?
How many ways are there to skin a cat?

 

[Rob Paisley]

Hi:

Since the LM3909 flasher chip is long out of production is there a
replacement chip or circuit that has the same or lower power consumption
(assuming the same LED was used on both)?
I did find a web page that implemented the schematic from the LM3909
using discrete components. Is this the lowest power consumption approach?

Thanks,

Brooke Clarke, N6GCE

You can reduce the curent draw of this circuit -
http://home.cogeco.ca/~rpaisley4/LM3909.html - by increasing the
values of the resistors in the circuit.

The circuit worked fine when R3 and R4 were doubled.

Rob.

 

[Jim Thompson]

You can reduce the curent draw of this circuit -
http://home.cogeco.ca/~rpaisley4/LM3909.html - by increasing the
values of the resistors in the circuit.

The circuit worked fine when R3 and R4 were doubled.

Rob.

Q2 should be diode driven (which is what that lateral PNP
representation is equivalent to). The website implementation may be
prone to leakage problems at high temperatures.

My attempt at ASCII:

---------------(5)
| |
\ | | /

|---+----|<

| | |
/| | | \
|_____| |
| |
(B) (C)



...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| Jim-T@analog_innovations.com Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

For proper E-mail replies SWAP "-" and "_"

Why is it that Democrats can't debate politely?
And are only rude and interruptive.
Lack of mental capacity?

 

[dan williams]

an 8 bit microprocessor is more efficient flashing a led than a 3909
was!!!???!!
somehow I have doubts...

dan

I recall seeing several brands of microcontrollers available in
8-pin packages, or other packages about the same size as an 8-pin DIP
(fully self-contained, flash-programmable, internal R-C oscillator)
that could be easily programmable as a "LED flasher", perhaps even
with flash speed controlled an external capacitor. Perhaps the best
for low current consumption would be the MSP430.
These are less than a dollar each. What did the LM3909 cost?
One possible problem is these things work at lower and lower
voltages, perhaps too low to light a blue LED.
How would this compare with a 555, either bipolar or CMOS version?
How many ways are there to skin a cat?

--
Dan Williams, Owner
Electronic Device Services
(604) 741 8431
RR8 855 Oshea rd
Gibsons BC Canada
V0N 1V8

 

[Watson A.Name - 'Watt Sun']

Q2 should be diode driven (which is what that lateral PNP
representation is equivalent to). The website implementation may be
prone to leakage problems at high temperatures.

My attempt at ASCII:

---------------(5)
| |
\ | | /
| | |
/| | | \
|_____| |
| |
(B) (C)



...Jim Thompson

I think he ought to rename it Dis-integrated Circuit.

One Q. I've seen the LMC555 (or other CMOS 555) working off a 1.5V
cell. How far below 1.5V does it work?


--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Fred Bloggs]

TI has some that are (loosely) spec'd at 1.0V.

http://www.scanti.ru/docs/datasheets/slfs044b.pdf


Best regards,
Spehro Pefhany

There are also those wall-clock chips produced by the gazzillions-
overkill for a LED flasher but will do the job nicely- and low voltage too.

 

[Michael Black]

The LM3909, originally called "The Miser", was designed by fellow MIT
class of 1962 grad Robert A. Hirschfeld back in the '60's.

Then he went on to become a lawyer, espoused father's rights in child
custody cases, and was ultimately disbarred here in Arizona a few
years ago ;-)

That name sounded familiar, and my memory was saying he wrote
an article about the LM370 for one of the ham magazines. But
being too lazy to try to find the article, I did a websearch,
and I was right, he apparently designed it and the others in
that sequence like the LM373.

I found a webpage about him and his legal battles, here:
http://www.nolawyer.com/badjudge/rahbio.html

My memory says the LM3909 didn't become available until some
years into the seventies, like maybe 1974. I had no idea
there was that much time between design and actual production.
But that webpage mentions he left National and founded Lithic Systems.
producing "the first radio transmitter on a chip". I remember
that, it was the LP2000, and I know I read about it in the fall
of 1972. I know I've mentioned the IC, for historical reasons,
a few times in the newsgroups, but apparently not by number.
I see you did post a detailed email from Bob about his designs,
back in 1998, which I don't remember reading before.

Michael

 

[Watson A.Name - 'Watt Sun']

Thanks for the info. So the CMOS 555 can serve as an alternative if
you don't mind the extra parts. But then, everyone knows the 555
astable circuit.

There are also those wall-clock chips produced by the gazzillions-
overkill for a LED flasher but will do the job nicely- and low voltage too.

But don't they need a xtal? Not something that you can come by
easily.


--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Watson A.Name - 'Watt Sun']

an 8 bit microprocessor is more efficient flashing a led than a 3909
was!!!???!!
somehow I have doubts...

dan

Yeah. Don't you just _love_ these short-sighted people that suggest
using a uC for a LED flasher? They have absoluely no consideration
for the roadblocks others would have to overcome with a uC. He said,
"..less than a dollar each." Did he _ever_ consider what the person
would have to pay for a programmer? No! And then the time the person
would have to spend programming, debugging, and burning the chip?
Didn't consider that either.

And there's the overkill factor. Like why to people insist on using
something like this to do such a simple job? I takes a couple
transistors and a few parts to flash a LED, not a microcontroller!

Ben Bradley wrote:
[snip]

I recall seeing several brands of microcontrollers available in
8-pin packages, or other packages about the same size as an 8-pin DIP
(fully self-contained, flash-programmable, internal R-C oscillator)
that could be easily programmable as a "LED flasher", perhaps even
with flash speed controlled an external capacitor. Perhaps the best
for low current consumption would be the MSP430.
These are less than a dollar each. What did the LM3909 cost?

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Lewin A.R.W. Edwards]

Since the LM3909 flasher chip is long out of production is there a

replacement chip or circuit that has the same or lower power consumption

BTW, did you know that there is a sub? (NTE876). Mouser carries it,
and it's in stock, though I dunno if it's in production.

 

[Tim Shoppa]

Thanks for the info. So the CMOS 555 can serve as an alternative if
you don't mind the extra parts.

Sort-of. The neat thing about the LM3909 is that when you run it off of
1.5V it delivers two-volt pulses to the LED. And when the battery is down
to 1.0V it's delivering about 1.5V to the LED, enough to be visible.

While on a fresh 1.5 cell a LMC555 will be blinking the LED, by the time
the cell voltage is down to 1.0V you won't be able to see the LED blink.
(Using a low-voltage incadescent bulb may do the trick, though.)

Tim.

 

[Mitch]

Both Mouser and B.G.Micro show stock availability on the LM3909. Be
prepared to pay a fortune for them though.

Mitch