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Topic: Attiny2313 minimum and maximum voltage? (Read 1 time)previous topic - next topic

navivanuva

Sep 19, 2013, 11:17 am
Hi,

Whats the minimum voltage for attiny 2313?  I read in the datasheet it can go as low as 2.7v.. But how come when i use 3v power supply it doesnt work?

Also how can i use 4 aa battery as the supply power? It doesnt seem to work too.. I guess, beacuse 4 aa battery is 6v while the maximum voltage is 5.5v?
Thanks!

baselsw

#1
Sep 19, 2013, 12:28 pm

Hi,

Whats the minimum voltage for attiny 2313?  I read in the datasheet it can go as low as 2.7v.. But how come when i use 3v power supply it doesnt work?

What's the clock frequency, 1Mhz, 8Mhz.. etc.. Can you post a schematic of how you connected everything maybe?? Would be a lot easier to help..
Quote

Also how can i use 4 aa battery as the supply power? It doesnt seem to work too.. I guess, beacuse 4 aa battery is 6v while the maximum voltage is 5.5v?
Thanks!

Well, why not use 3 AA batteries (~4.5V)??  Anyway, to be able to drop 6V to 5V you need a low dropout regulator.. Here is an example: http://www.ti.com/lit/ds/snvs096d/snvs096d.pdf

//Basel

fungus

#2
Sep 19, 2013, 02:15 pm

Hi,

Whats the minimum voltage for attiny 2313?  I read in the datasheet it can go as low as 2.7v.. But how come when i use 3v power supply it doesnt work?

How should we know? It will depend on your circuit.

Also how can i use 4 aa battery as the supply power? It doesnt seem to work too.. I guess, beacuse 4 aa battery is 6v while the maximum voltage is 5.5v?

If you've applied 6V that might explain why it doesn't work any more.

PS: AA batteries are only 1.5V for a tiny fraction of their life. Most of the time they're 1.25V (yes, it varies).
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

john1993

#3
Sep 19, 2013, 07:11 pm
aa alkalines start out at 1.6-1.7v, level off at 1.5v, and are pretty much depleted at 1.4v. 3 cells would make an excellent avr dc supply. 2313 from the factory runs fine at 3v and even down to less than 1.8v in my experience.

tylernt

#4
Sep 19, 2013, 08:37 pm

aa alkalines start out at 1.6-1.7v, level off at 1.5v, and are pretty much depleted at 1.4v.
Most new batteries out of the pack that I've tested come in at 1.55 OCV (Open Cell Voltage). These include AAA, AA, and D Energizer, Rayovac, and Duracell. So 1.55V x 4 = 6.2V = fried ATTiny AVR.

(Energizer Lithium AA/AAA, by the way, is usually 1.8 OCV out of the pack!)

When a cell is "dead' depends on the load you put on it. An alkaline at 1.4 OCV could be put in a clock or remote control and last for months, but try to use it in a bright LED flashlight or with a big motor and it'll fall flat on it's face. As OCV falls, the amount of current the cell can source falls. I find most devices are done with alkalines at about 1.2 OCV, but YMMV.

fungus

#5
Sep 19, 2013, 08:54 pm

aa alkalines start out at 1.6-1.7v, level off at 1.5v, and are pretty much depleted at 1.4v.

I'm going to have to disagree with that:

"Depletion" is more like 1.1V.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

john1993

#6
Sep 20, 2013, 12:26 amLast Edit: Sep 20, 2013, 12:27 am by john1993 Reason: 1
i suppose it depends on what you mean by "depletion" but that first graph anyway does not seem too dependable showing starting voltage at 1.5v. way too low. here any lots that show 1.5v when new we return as old or defective. imo 1.1v is an appropriate discharged level for nixx.

in my experience alkalines at 1.4v have around 10% life left and are discarded. im sure others may be happy continuing use with that margin but i toss them rather than risk it.

tylernt

#7
Sep 20, 2013, 01:13 am

in my experience alkalines at 1.4v have around 10% life left and are discarded. im sure others may be happy continuing use with that margin but i toss them rather than risk it.
Like I said, it depends on how much current you are drawing from them. You must have a high drain application? Or some device that's very voltage sensitive. At 1.4V you're tossing cells with plenty of mAh left in them.

BTW for high drain applications, NiMH can outperform alkalines. Even though the OCV of NiMH is lower, voltage under load can be higher because they have less internal resistance and can deliver more current.

navivanuva

#8
Oct 03, 2013, 05:22 am

It is working now.. I finally use 9v battery and 7805 power regulator. and it works well..
THANKS ALL

fungus

#9
Oct 03, 2013, 10:28 am

I read in the datasheet it can go as low as 2.7v.. But how come when i use 3v power supply it doesnt work?

You must be doing it wrong....

We can't help you because we can't see what you're doing from here.

Also how can i use 4 aa battery as the supply power?

Not easily. Normally you need to use either 6 or 3 AA batteries.

4/5 batteries don't really work.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

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