I have searched on this, but perhaps I have the wrong search terms...
I'm looking for pin-compatible TO220 (ie drop-in) replacement parts for 7815 and 7915. I have seen advice here to use LM317 and LM337 on small bits of veroboard, but my application is too space-limited to do this, and on paper that gives no improvements in regulation or output noise over the fixed parts anyway.
Any suggestions, or links to blatently obvious threads that I've missed?
I'm looking for pin-compatible TO220 (ie drop-in) replacement parts for 7815 and 7915. I have seen advice here to use LM317 and LM337 on small bits of veroboard, but my application is too space-limited to do this, and on paper that gives no improvements in regulation or output noise over the fixed parts anyway.
Any suggestions, or links to blatently obvious threads that I've missed?
I don"t think there are any drop in replacements for those regulators not ones that will provide better performance...
becides the LM317/337 regulators (Which should be able to drop in with only a couple small changes to allow for a Diode and 2 resistors One of which can be mounted to the regulator as well as the Diode)
I suppose if you were in a Pinch you could use a Resistor and a Zener Diode as a regulator but it would not offer any improved performance......
Cheers
becides the LM317/337 regulators (Which should be able to drop in with only a couple small changes to allow for a Diode and 2 resistors One of which can be mounted to the regulator as well as the Diode)
I suppose if you were in a Pinch you could use a Resistor and a Zener Diode as a regulator but it would not offer any improved performance......
Cheers
http://www.newclassd.com/index.php?page=70
You only have to wait for the 79xx variant and I do not know if those are planned... BTW I haven't used them so I can't comment on quality etc.
You only have to wait for the 79xx variant and I do not know if those are planned... BTW I haven't used them so I can't comment on quality etc.
LM2990
LM2990
As a pin-compat with 78xx (centre ground pin), the LDO LM2940 fits the bill, but they don't come in 79xx equivalents. And whether or not they're an improvement on 78xx, I've no idea.
LM2990
An old thread but still interesting as new parts are being developed. The current OnSemi MC7815 and MC7915 have much better specs than the original 78xx and 79xx series. The datasheet has been updated as a result of that.
Please compare the OnSemi MC78xxAC and MC78xxCTG and choose the type with the best specs for your application. They have different specs. This also counts for the negative variant of course.
Please note that the negative 15V variant that OnSemi produces has only 90 uV noise. That is way lower than 7915 types of other manufacturers. For example National's LM7915 has 375 uV noise ....
Always use output caps, certainly with 79xx and make sure the load draws some mA otherwise the output might be unstable. This is considered to be common knowledge but it is done wrong in many devices. A simple solution is to connect the power LED at the negative regulators output.
Please compare the OnSemi MC78xxAC and MC78xxCTG and choose the type with the best specs for your application. They have different specs. This also counts for the negative variant of course.
Please note that the negative 15V variant that OnSemi produces has only 90 uV noise. That is way lower than 7915 types of other manufacturers. For example National's LM7915 has 375 uV noise ....
Always use output caps, certainly with 79xx and make sure the load draws some mA otherwise the output might be unstable. This is considered to be common knowledge but it is done wrong in many devices. A simple solution is to connect the power LED at the negative regulators output.
LM340T-05 is an example of an equivalent part number.
But if you look around you will find many many many variations of the "78xx" series, from many vendors. Not all are the same. No two are the same. Yet people lump them together, and base their opinions and advice on their (usually bad) experience with just one of them. You can find low noise 78xx series with good PSRR, good load regulation, and overall very good specs. You can also find downright crappy ones. Not all are equal.
Same goes for "5532" opamps. People tend to forget or ignore, inexplicably, that many different vendors produce "5532" opamps and that no two are the same, except for similar specs around noise, bandwidth, etc.
But if you look around you will find many many many variations of the "78xx" series, from many vendors. Not all are the same. No two are the same. Yet people lump them together, and base their opinions and advice on their (usually bad) experience with just one of them. You can find low noise 78xx series with good PSRR, good load regulation, and overall very good specs. You can also find downright crappy ones. Not all are equal.
Same goes for "5532" opamps. People tend to forget or ignore, inexplicably, that many different vendors produce "5532" opamps and that no two are the same, except for similar specs around noise, bandwidth, etc.
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