LM3909

johndoe99

I was looking to build a circuit using the LM3909 oscillator IC, but this chip is long out of production. Can anyone tell me if there's an alternative IC that has the same low power consumption.

I know i can make an alternative circuit, but space is an issue.

Thanks.

mawk

This crowd have quite a few of them for smallish money.

http://www.ebay.ie/itm/1pcs-LM3909-LM3909N-LED-Flasher-Oscillator-IC-ICS-/330469368157?pt=LH_DefaultDomain_0&hash=item4cf182615d#ht_3439wt_943

johndoe99

mawk wrote: »

This crowd have quite a few of them for smallish money.

http://www.ebay.ie/itm/1pcs-LM3909-LM3909N-LED-Flasher-Oscillator-IC-ICS-/330469368157?pt=LH_DefaultDomain_0&hash=item4cf182615d#ht_3439wt_943[/QUOTE]

thanks, but was hoping to find somewhere closer to home, shame that they discontinued them.

gooch2k9

Annoying when they discontinue the ICs! Had the same problem with keypad decoders, nabbed some cheap enough off Ebay, only found one auction globally though. Seems they don't make a lot of these ICs any more as a cheap micro can do their functions and more, and cost less.

I'd say the ones on Ebay are your best hope if you're dead set on using that chip.

johndoe99

gooch2k9 wrote: »

Annoying when they discontinue the ICs! Had the same problem with keypad decoders, nabbed some cheap enough off Ebay, only found one auction globally though. Seems they don't make a lot of these ICs any more as a cheap micro can do their functions and more, and cost less.

I'd say the ones on Ebay are your best hope if you're dead set on using that chip.

I've sent a few enquiries off to the big names, see if they can provide a solution/alternative IC.

If not i'll order from ebay.

DublinDilbert

Can you post a pic or a link to your schematic?

It looks like a 555 timer should be able to do what that IC does if its configured correctly...

johndoe99

DublinDilbert wrote: »

Can you post a pic or a link to your schematic?

It's in my head, only ever draw it up in CAD once i have all the kinks worked out.

DublinDilbert wrote: »

It looks like a 555 timer should be able to do what that IC does if its configured correctly...

I already considered the 555, the LM3909 only draws 0.5mA. Whereas the 555 draws 2.2mA. My circuit is based primarily that it can function for 9 months on a 3v battery.

I'm also considering adding a redundant solar panel to increase the battery life further, but thats a whole other story.

I designed the circuit believing I already had a few spare 3909's.

DublinDilbert

You'll get a 555 timer that uses less power than 2.2mA. We used to use them in low power applications to wake up automotive ecu's before cpu's had various sleep timers built in.

If your driving led(s) they are going to consume much more than 2.2mA, so the 555 current draw will be irrelevant.

johndoe99

What i like most about the 3909 is that it pulses volts to the LED and that it can last nearly a year from 1.5v.

i think your refering to the 7555 low power timer, i never actually considered that. I'll throw together a circuit on my protoblock and see if it meets my needs. Thanks.