Somthing better than the LM7812

Nounours18200 · 26th March 2012, 07:23 PM

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

AndrewT · 26th March 2012, 08:19 PM

lm317

Andersonix · 29th March 2012, 07:16 AM

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.

Nounours18200 · 5th April 2012, 07:30 PM

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 !

benb · 5th April 2012, 11:29 PM

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.

thov · 6th April 2012, 12:59 AM

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.

goodwill · 8th April 2012, 04:37 PM

Quote:

Originally Posted by thov

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!!

Wirehead.be · 10th April 2012, 09:22 AM

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.

syklab · 10th April 2012, 09:51 AM

How about the LT1084CP12? It is a LDO reg and supposed to be able to handle a max output current of 5A.

AndrewT · 10th April 2012, 09:57 AM

LDOs can be quite intolerant of reactance on the output.

26th March 2012, 07:23 PM	#1
Nounours18200 diyAudio Member Join Date: Jan 2004 Location: GRASSE (France)	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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26th March 2012, 08:19 PM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	lm317

29th March 2012, 07:16 AM	#3
Andersonix diyAudio Member Join Date: Jan 2004 Location: Silicon Valley	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.

5th April 2012, 11:29 PM	#5
benb diyAudio Member Join Date: Apr 2010	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.

10th April 2012, 09:22 AM	#8
Wirehead.be diyAudio Member Join Date: Nov 2006	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.

10th April 2012, 09:51 AM	#9
syklab diyAudio Member Join Date: Jul 2009 Location: Hong Kong	How about the LT1084CP12? It is a LDO reg and supposed to be able to handle a max output current of 5A.

10th April 2012, 09:57 AM	#10
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	LDOs can be quite intolerant of reactance on the output.