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RE: [AVR-Chat] Off topic - general electronics question

2004-02-13 by Claxton, Dean J

Thanks Al,

I believe that would be what it is.

Would you have any idea where I can get one cheaply? Seems Farnell sell
them, but AU$22.83 + GST each.

Regards

Dean Claxton

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-----Original Message-----
From: Al Welch [mailto:alwelch@axxiomchromatography.com] 
Sent: Friday, 13 February 2004 2:42 AM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Off topic - general electronics question

Linear TEchnology makes a LT1375, 8-pin step down voltage regulator.

Al Welch

-----Original Message-----
From: Claxton, Dean J [mailto:dean.j.claxton@team.telstra.com]
Sent: Wednesday, February 11, 2004 9:15 PM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Off topic - general electronics question

Surface mount 8 pin device on the back of a video card - marked "1375
pncn" - any ideas what it is??

Could it be some type of voltage regulator?

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RE: [AVR-Chat] Off topic - general electronics question

2004-02-13 by Al Welch

Digikey shows them for under $7 in the USA. I note there is a -5 for fixed 5
volt output and a no dash for adjustable output.
I think you can buy direct from Linear Technology using a credit card as
well.

Al

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-----Original Message-----
From: Claxton, Dean J [mailto:dean.j.claxton@team.telstra.com]
Sent: Thursday, February 12, 2004 7:21 PM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Off topic - general electronics question

Thanks Al,

I believe that would be what it is.

Would you have any idea where I can get one cheaply? Seems Farnell sell
them, but AU$22.83 + GST each.

Regards

Dean Claxton

-----Original Message-----
From: Al Welch [mailto:alwelch@axxiomchromatography.com]
Sent: Friday, 13 February 2004 2:42 AM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Off topic - general electronics question

Linear TEchnology makes a LT1375, 8-pin step down voltage regulator.

Al Welch

-----Original Message-----
From: Claxton, Dean J [mailto:dean.j.claxton@team.telstra.com]
Sent: Wednesday, February 11, 2004 9:15 PM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Off topic - general electronics question

Surface mount 8 pin device on the back of a video card - marked "1375
pncn" - any ideas what it is??

Could it be some type of voltage regulator?

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RE: [AVR-Chat] Off topic - general electronics question

2004-02-13 by Mike Murphree

Al Welch said:
> Digikey shows them for under $7 in the USA. I note there is a -5 for
> fixed 5 volt output and a no dash for adjustable output.
> I think you can buy direct from Linear Technology using a credit card as
> well.

I would advise anyone using Linear Technology's regulators to study the
datasheets closely first.  Some of their low-noise regulators that I used
on my last project had very specific rules regarding capacitor types and
values else they won't behave as advertised...

Mike

RE: [AVR-Chat] Off topic - general electronics question

2004-02-13 by Al Welch

I use Liner Techs SwitcherCad (free to download and use) to simulate the
power supply. It seems to work great for this. It does make a great deal of
difference when you select a low ESR cap instead of a cheapo when it comes
to noise filtering. I just got done with a +/-5, +3.3v supply using their
spice software. I found a diode that was being abused by looking at the
current flowing in that part using SwitcherCad. I have been using their
regulators for a number of years and am very satisfied with them. They seem
to require fewer parts to get the job done.

Al Welch

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-----Original Message-----
From: Mike Murphree [mailto:mike@tropo.org]
Sent: Friday, February 13, 2004 9:59 AM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Off topic - general electronics question

Al Welch said:
> Digikey shows them for under $7 in the USA. I note there is a -5 for
> fixed 5 volt output and a no dash for adjustable output.
> I think you can buy direct from Linear Technology using a credit card as
> well.

I would advise anyone using Linear Technology's regulators to study the
datasheets closely first.  Some of their low-noise regulators that I used
on my last project had very specific rules regarding capacitor types and
values else they won't behave as advertised...

Mike

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Re: [AVR-Chat] Off topic - general electronics question

2004-02-14 by Mike Murphree

On Feb 13, 2004, at 4:34 PM, Al Welch wrote:

> I use Liner Techs SwitcherCad (free to download and use) to simulate 
> the
> power supply. It seems to work great for this. It does make a great 
> deal of
> difference when you select a low ESR cap instead of a cheapo when it 
> comes
> to noise filtering. I just got done with a +/-5, +3.3v supply using 
> their
> spice software. I found a diode that was being abused by looking at the
> current flowing in that part using SwitcherCad. I have been using their
> regulators for a number of years and am very satisfied with them. They 
> seem
> to require fewer parts to get the job done.

These were linear regulators and not switchers.  They required tantalum 
(expensive) and not conventional electrolytics.  Their stability was 
not good without tantalums.  Just seemed a bit extreme to me...

If you want to do serious switcher work, take a look at Ridley 
Engineering's Power 4-5-6 software.

Mike