LM series regulators from ST = TRASH - diyAudio
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Old 12th September 2007, 11:25 AM   #1
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Thumbs down LM series regulators from ST = TRASH

Hi there,

DON'T buy ST regulators, they are BAD. My devices are GENUINE, and my LM7915 gives-me -16,5v while my National give me -14,92v.

I don't like much ST. Their power transistors are much more difficul to match than Fairchild for example, and I had a bad experience with their regulators today. I'm using their AMP, TDA7293V, and it performs VERY WELL despite the other bad experiences...

Best Regards !
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Old 12th September 2007, 12:00 PM   #2
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Default Re: LM series regulators from ST = TRASH

Quote:
Originally posted by -_nando-_
Hi there,

DON'T buy ST regulators, they are BAD. My devices are GENUINE, and my LM7915 gives-me -16,5v while my National give me -14,92v.
Hi,

No load during your test? At least 5mA is required in order for the regulator to function properly.
-16.5V is way out of spec.
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Old 12th September 2007, 12:40 PM   #3
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Exactly, do read the datasheet!
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Old 12th September 2007, 01:31 PM   #4
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Also, I found you need !uF of output capacitance to avoid oscillation on the negative regulators whereas you only need 0.1uF with the positive ones.
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Old 12th September 2007, 02:58 PM   #5
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79xx and 78xx are quite different if you check the simplied schematics.
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Old 13th September 2007, 03:57 AM   #6
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I didn't test it with a load, but it have a 100nF cap on it's output. Without load, the regulator from National gives a good voltage regulation, while the ST don't. I didn't test ST with load, as I tested it and after the reading I replaced immediatelly.
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Old 13th September 2007, 05:13 AM   #7
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BC550 from ON is not 100% compatible with BC550 from Fairchild. The same goes for these regulators.
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Old 18th September 2007, 03:18 AM   #8
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Oscillation???
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Old 18th September 2007, 06:35 AM   #9
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No oscilation
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Old 19th September 2007, 10:13 AM   #10
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Quote:
Originally posted by -_nando-_
I didn't test it with a load, but it have a 100nF cap on it's output. Without load, the regulator from National gives a good voltage regulation, while the ST don't. I didn't test ST with load, as I tested it and after the reading I replaced immediatelly.
Don't blame the regulator then if you did not use a load, the datasheet says it needs a minimum load.
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