Hi all, I'm looking for a product code and a source for a LDO Linear
Regulator with the following specs:

V in = +3.3 or +5.0 V
V out = +2.9 +/- 0.1 V
I out = 8A min.

TIA,
Eric

Eric wrote:
Hi all, I'm looking for a product code and a source for a LDO Linear
Regulator with the following specs:

V in = +3.3 or +5.0 V
V out = +2.9 +/- 0.1 V
I out = 8A min.

There is a LT317A that is a voltage regulator, wich you regulate output
of with a resistor (fixed or pot). I dunno if these take 8A, but maybe
worth a google...Also, you can use a 7803 wich would give 3V out,
according to the refference point. If you can set that refference point
to 0,1V above real ground (Hint: Voltage divider resistors), voila, you
have 2,9V.

On Sat, 02 Oct 2004 19:48:12 GMT, Vidar Løkken
wrote:

Eric wrote:
Hi all, I'm looking for a product code and a source for a LDO Linear
Regulator with the following specs:

V in = +3.3 or +5.0 V
V out = +2.9 +/- 0.1 V
I out = 8A min.

There is a LT317A that is a voltage regulator, wich you regulate output
of with a resistor (fixed or pot). I dunno if these take 8A, but maybe
worth a google...Also, you can use a 7803 wich would give 3V out,
according to the refference point. If you can set that refference point
to 0,1V above real ground (Hint: Voltage divider resistors), voila, you
have 2,9V.


A linear reg means ( 5 volts - 2.9 volts ) x 8amps = 16.8 watts.
Thats a lot of heat to dump. Plus, I think you need at leat 0.5 volts
higher on the input side of a 78xx than the output side.

You can increase the current capacity of a 78xx regulator by using
some surrounding circuity with a higher current transistor, but I
think you'll still have the 0.5 differential limitation.

I think you really need to look at a switching type of regulator.


-Chris

"Eric" wrote in message
...
| Hi all, I'm looking for a product code and a source for a LDO Linear
| Regulator with the following specs:
|
| V in = +3.3 or +5.0 V
| V out = +2.9 +/- 0.1 V
| I out = 8A min.

723 and a pass transistor? That's not much of a drop.

N

wrote in message
...
On Sat, 02 Oct 2004 19:48:12 GMT, Vidar Løkken
wrote:

Eric wrote:
Hi all, I'm looking for a product code and a source for a LDO Linear
Regulator with the following specs:

V in = +3.3 or +5.0 V
V out = +2.9 +/- 0.1 V
I out = 8A min.

There is a LT317A that is a voltage regulator, wich you regulate output
of with a resistor (fixed or pot). I dunno if these take 8A, but maybe
worth a google...Also, you can use a 7803 wich would give 3V out,
according to the refference point. If you can set that refference point
to 0,1V above real ground (Hint: Voltage divider resistors), voila, you
have 2,9V.


A linear reg means ( 5 volts - 2.9 volts ) x 8amps = 16.8 watts.
Thats a lot of heat to dump. Plus, I think you need at leat 0.5 volts
higher on the input side of a 78xx than the output side.

You can increase the current capacity of a 78xx regulator by using
some surrounding circuity with a higher current transistor, but I
think you'll still have the 0.5 differential limitation.

I think you really need to look at a switching type of regulator.


-Chris

The 78xx regulators won't work, even with external current boost circuitry.
They need at least 2.5 volts across the regulator...
And although there are several adjustable linear regulators available,
you're going to be hard-pressed finding one that will handle 8A. most
likely, you're gonna have to build a switcher that will operate at those low
voltages.

--
Dave M
MasonDG44 at comcast dot net (Just subsitute the appropriate characters in
the address)

Never take a laxative and a sleeping pill at the same time!!