Wayne, thanks for your introduction of this regulator! It is the best
method to provide a stable 1.35V output. Since Linear Tech only
mentioned min 1.8V input voltage, I have a little concern, but as you
have tested it I think it should be okay. We need only a small
current, may be the IC can tolerate a little lower in input voltage.
Jim, you cannot use alkaline, its output voltage will drop with time,
we need at least 0.1V voltage different to work. Silver oxide is the
only choice. If my memory serve, normal SR44 is around 160mA hour at
20uA quiescent current, the standby time is around one year.
C.H.Ling
Jim Sharp wrote:
>
> I wondered why nobody had mentioned something like this before. This should
> work fine.
>
> The nice thing about this method is you can probably use cheepo alkaline
> batteries that are available anywhere. The regulator will take care of the
> battery voltage drop over time.
>
> I work with surface mount electronics all the time but I haven't been brave
> enough to open up my OM-1 to see where this circuit could go...
>
> The link to the regulator data sheet is
>
> http://www.linear-tech.com/cgi-bin/database?function=elementinhtml&filename=DataSheet.html&name=DataSheet&num=594
>
> Or just go to http://www.linear-tech.com and search for 1761
>
> --
> Jim
>
> >For anyone interested in a battery replacement for a 1.35V mercury
> >cell, I just tested one of our (Linear Technology) LDO regulators (low
> >drop out regulator) and it seems to work. The part is the LT1761. (see
> >www.lineartech.com for the data sheet). For an input I used a 1.5V
> >source (1.5-1.55V is typical for silver oxide battery) and the
> >regulated output was 1.35V. The part draws 20uA of quiescent current
> >and easily handled 300uA load, which is probably more than enough for
> >an OM-1. The part requires two external adjust resistors to set the
> >output level and an output bypass cap of 1uF (see page 12 of the
> >datasheet for the circuit). I used a 1.5Meg and a 193K resistor to set
> >the output to 1.35V. The part is in a tiny SOT-23 package. The circuit
> >can be turned off by putting it in series with the off switch or by
> >using an optional shutdown pin. I have half a dozen parts if anyone
> >would like one to try for them self. Requires good soldering skill.
> >
> >Wayne
>
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