need to step up 3V (2 AA) to 5V for a USB devicer (max draw

can anyone point me to an IC that i could use to fairly simply and
efficiently step 3v from 2 AA cells to 5V for powering a USB device. i
have been searching and have come up with a few, but im not exactly
sure what i should look for.

if you could also let me know any other components i will need, and a
basic run through of how to set it up i would appreciate it a lot.
thanks

 

[John Larkin]

On 25 Jan 2005 14:33:57 -0800, zip2two@gmail.com wrote:

can anyone point me to an IC that i could use to fairly simply and
efficiently step 3v from 2 AA cells to 5V for powering a USB device. i
have been searching and have come up with a few, but im not exactly
sure what i should look for.

if you could also let me know any other components i will need, and a
basic run through of how to set it up i would appreciate it a lot.
thanks

National Semiconductor's web site will pick a part for you and design
the circuit, all online.

John

 

thanks for the resource.

using the requirements of Vin = 2.2 - 3 V and Vout = 5V Iout = .5 A i
came up with a LM2702-ADJ. the other features such as building the
circuit are not offered for this product (at least i didnt see the
options like it shows in the help video). any further assitance would
be appreciated

 

[Nicholas O. Lindan]

<zip2two@gmail.com> wrote

can anyone point me to an IC that i could use to fairly simply and
efficiently step 3v from 2 AA cells to 5V

Go to the Maxim site. If you don't like
Maxim then try Linear Technology.

These are standard parts [as standard as things get these days...]

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

 

Nicholas O. Lindan wrote:

Go to the Maxim site. If you don't like
Maxim then try Linear Technology.

These are standard parts [as standard as things get these days...]

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Alright, I am coming up with some things that seem like they would work
at the sites I am being sent to, but I still havent recieved any solid
guidance. I would appreciate it if someone could tell me the
appropriate parts and help me figure out the other pieces I will need.
Im sorry Im such a beginner, but I really appreciate any help.

 

[Jeroen]

"Nicholas O. Lindan" <see@sig.com> wrote in message
news:CDBJd.9882$rp1.4654@newsread3.news.atl.earthlink.net...

zip2two@gmail.com> wrote

can anyone point me to an IC that i could use to fairly simply and
efficiently step 3v from 2 AA cells to 5V

Go to the Maxim site. If you don't like
Maxim then try Linear Technology.

Is going with either Maxim or LT a personal preference?

Jeroen

 

[Nicholas O. Lindan]

"Jeroen" <jayjay.1974@xs4all.nl> wrote

Is going with either Maxim or LT a personal preference?

For some, yes. Maxim had a bad shortage situation that they
handled very badly. There is a lot of bad feeling towards
Maxim as a result. Some firms have a 'No Maxim' policy
on new designs - stupid as that may seem: wait long
enough and you'll get screwed at least once by everybody
and everybody will be on the blacklist.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

 

[malvarezdel]

Why not simply take the 5V from USB? I have done that without any
problem....If you don´t need more than 500 mA it will work for you.

 

[Mac]

On Tue, 25 Jan 2005 16:21:35 -0800, zip2two wrote:

thanks for the resource.

using the requirements of Vin = 2.2 - 3 V and Vout = 5V Iout = .5 A i
came up with a LM2702-ADJ. the other features such as building the
circuit are not offered for this product (at least i didnt see the
options like it shows in the help video). any further assitance would
be appreciated

You might as well allow Vin go all the way down to 2.0 V. Maybe even
1.8. The lower you go, the more you will get out of your batteries,
although there isn't any point in going below 1.6, I think. Also, fresh
batteries are about 1.6V each, so you might want to go up to 3.2. Then
again, as soon as you start draining at 700 mA or whatever, the Voltage
should drop instantly, so maybe 3.0 is a good upper limit after all.

By the way, how long do you need the batteries to last? I don't think
AA's are going to last very long with a drain of 800 - 1500 mA. I doubt
you will even get two hours out of a fresh set of batteries.

--Mac