How long would a 3V button cell lithium battery last

[80k]

I'm talking about those batteries used in watches... those tiny button cells.

I was reading AMZ's article on 1.5 or 3V boosters, and i started wondering about the lithium watch batteries, since they come in both 1.5 and 3 volts.

not really sure what to look for in terms of specs, but just wondering if anyone knew approximately how long it would last in a boost circuit with like one transistor, and no LED.  i am really curious to know whether it is even practical!

[aron]

I can't find info on it.

[niftydog]

any idea of the current draw on the boosters?

That'd be the important thing. Even fancy button batterys are only rated to 150mAh or so... but the actuall discharge time depends on a number of factors.

[gez]

http://www.intersil.com/data/fn/fn2919.pdf

ICL7611 op-amp.  Can be run as low as 2V.  Quiescent current can be set via pin 8 to a mere 100uA.  Rail-to-rail output.  Ideal for this application.  If I recall, Mouser sell them in the US (rapid, esr & Maplin in UK).

At 3V, I'd use them for buffers/filters but not much else (most boosters are going to clip).

[gez]

Rapid sell a 3V 'lithium coin cell' made by Sony whose capacity is 560mAh.  With the ICL7611 that's 233 days of life (assuming no input signal)!  :lol:

[niftydog]

short-form datasheet for said battery.

note the maximum recommended continuous discharge current is 3mA. Keep it below that and it should be happy.

Also be aware that the mAh rating is given in ideal circumstances, and at 3mA draw it will be significantly less than the 550mAh quoted.

[gez]

Rapid sell a 3V 'lithium coin cell' made by Sony whose capacity is 560mAh.  With the ICL7611 that's 233 days of life (assuming no input signal)!

Also assumes no bias resistors are used! Couple of 150ks should do nicely.

[petemoore]

I'ts cool to read you're using the Low Voltage article at AMZ as I have for researching designs.
 As shown in the article, very nice designs...simple and effective, a less traveled route for one reason or another...
 Though scheamtics and boxes with LV have been around for a long time, there's not a whole lot of 'history' about them...
  Probably [as I ramble] there was limited interest in the designs after 9v became the norm ....'because'...higher output, more headroom to start with, 1v worth of battery drop is 1/9th [as opposed to 1/3], of a fresh battery...and they don't tend to distort with large signal inputs...designers, end users...who wouldn't be tempted to pick just one battery type....and a regulator means draw...3v got mostly sidelined...for some reason[s...
  For our uses though...considering the difficulty and price of a regulator [which I'd recommend trying with such circuits] 3v is not a difficult option.
 Because the PS input voltage directly sets headroom, and in this case soft clipping, being able to move it around with a regulator has obvious advantages.
 I was working with these boosters for a time a short while ago, [it kind of got a problem I haven't messed with after ALot of resolderings and parts swaps...I should have used more sockets and larger board/breadboard]..
 At any rate, using the regulator and seriesed diodes to drop the PS voltage even further on one of the 2-3 stages I had going...I found an easily dialable pallette [different soft Dist tones] could be had with seriesed gain stages and a few knobs...add in some 9v effects...
 If you desire soft clipping, LV offers a relatively easy, unique option to explore.
 Since very little of any of this is verified, I can't say for sure whether it was a fluke, but a very pronounced 'dip' compression [attenuation then bloom of HV source input ... like loud low notes] a considerably 'different' one trick pony sound, very fun and great sounding to play with. I can't tell you exactly how I got it, but suspect it's 'there' and can be found easily enough.
 Perhaps I soon pull that board up and do some inspecting and rebuilding...EZ/Fun to mess with, LV offers a different angle of approach to soft Fuzz.

[80k]

cool thanks for the responses.

petemoore, that's interesting stuff.  i think i'll really have to explore the low voltage option soon.  sounds really cool!  do you use AAA batteries mostly?