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Old 26th March 2012, 07:23 PM   #1
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Default Somthing better than the LM7812

Hi friends,

I currently upgrade a Power Supply card for a DAC, which uses two LM-7812 voltage regulators.

I would just like to ask you if you know another chip that would be better than the LM7812 ?

Tks
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Old 26th March 2012, 08:19 PM   #2
AndrewT is online now AndrewT  Scotland
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lm317
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Old 29th March 2012, 07:16 AM   #3
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Maybe you could ask Murata for a couple of samples of their switching regulator 7812SR? I tried a 7805SR for the DAC in my Oppo DVDP and liked it. (But they're $10 at D-K...)

I'm just sorry there's no Negative version.
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Old 5th April 2012, 07:30 PM   #4
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Quote:
lm317
Can I just remove the LM7812 and replace it by a LM317 ?

In which area(s) is the LM317 better than the LM7812 ?

Thanks !
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Old 5th April 2012, 11:29 PM   #5
benb is offline benb  United States
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No, pinout is absolutely different and incompatible. The LM317 needs two resistors that need to be chosen to set the output voltage: It might also need different capacitors on input and/or output for best operation.
LM317 - 3-Terminal Adjustable Regulator
While I haven't looked into it, I've read it has lower noise than the common fixed-output regulators such as 7812. Get the datasheets of both and compare them, that should answer a lot of questions.

As for the Murata part, it would be a hard sell for me to consider a switching regulator, regardless of the price. It's hard to believe it wouldn't generate substantially more noise than any linear regulator.
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Old 6th April 2012, 12:59 AM   #6
thov is offline thov  Denmark
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The 723 voltage regulator will be better than any 3-pin regulator.
The downside is the number of additional components, and limited power capability (300mA).
Fortunately it's easy to increase power handling by adding an NPN power transistor.
With the BC140 it will match the 7812, but for more power even the old workhorse 2N3055 will do the trick.
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Old 8th April 2012, 04:37 PM   #7
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Quote:
Originally Posted by thov View Post
The 723 voltage regulator will be better than any 3-pin regulator.
The downside is the number of additional components, and limited power capability (300mA).
Fortunately it's easy to increase power handling by adding an NPN power transistor.
With the BC140 it will match the 7812, but for more power even the old workhorse 2N3055 will do the trick.
Hi friends, I recently want to replace my NAS switching supply with a linear one. Is this circuit suitable for use?
I need 12V 3A output, just replace BC140 with 2N3055 ok?
Thanks a lot!!
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Old 10th April 2012, 09:22 AM   #8
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MC7812 (On-Semi) are drop-in replacements; and have better specs than the average LM7812; nobody seems to use them here though - but they look promising.
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Old 10th April 2012, 09:51 AM   #9
syklab is offline syklab  Hong Kong
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How about the LT1084CP12? It is a LDO reg and supposed to be able to handle a max output current of 5A.
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Old 10th April 2012, 09:57 AM   #10
AndrewT is online now AndrewT  Scotland
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LDOs can be quite intolerant of reactance on the output.
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