Low noise voltage regulators.

[Davemar]

I need some low noise voltage regulators for a audio circuit I intend
to build. I could just use some 78xx & 79xx 3-pin cheapy regulators,
but I think they tend to be quite noisy. Are there any more modern
alternatives that offer decent low noise performance? Something that's
a simple 3-pin design would be preferable. I'm looking at +/-12 or 15v
and <300mA current consumption fot the circuit.

 

[Jim Meyer]

I need some low noise voltage regulators for a audio circuit I intend
to build. I could just use some 78xx & 79xx 3-pin cheapy regulators,
but I think they tend to be quite noisy. Are there any more modern
alternatives that offer decent low noise performance? Something that's
a simple 3-pin design would be preferable. I'm looking at +/-12 or 15v
and <300mA current consumption fot the circuit.

Actually the lowest noise voltage regulator isn't a more modern
one but a more ancient one. The venerable LM723 has noise voltage
outputs in the microvolt range.

Sometimes newer *isn't* better.

Jim

 

[Davemar]

Actually the lowest noise voltage regulator isn't a more modern
one but a more ancient one. The venerable LM723 has noise voltage
outputs in the microvolt range.

Sometimes newer *isn't* better.

That old thing haven't seen one of those in years. I'm sure I'll have
collecting dust at the back of some cupboard somewhere!

 

[Robert Baer]

I need some low noise voltage regulators for a audio circuit I intend
to build. I could just use some 78xx & 79xx 3-pin cheapy regulators,
but I think they tend to be quite noisy. Are there any more modern
alternatives that offer decent low noise performance? Something that's
a simple 3-pin design would be preferable. I'm looking at +/-12 or 15v
and <300mA current consumption fot the circuit.

Err..why bother, when a well designed amplifier has at least 60dB of
PSRR.

 

[Robert Baer]

That old thing haven't seen one of those in years. I'm sure I'll have
collecting dust at the back of some cupboard somewhere!

uA723 parts are still cheap and available.

 

[Spehro Pefhany]

uA723 parts are still cheap and available.

In SOIC-14, even. Obviously they are being used in relatively new
designs.

Best regards,
Spehro Pefhany

 

[John Larkin]

I need some low noise voltage regulators for a audio circuit I intend
to build. I could just use some 78xx & 79xx 3-pin cheapy regulators,
but I think they tend to be quite noisy. Are there any more modern
alternatives that offer decent low noise performance? Something that's
a simple 3-pin design would be preferable. I'm looking at +/-12 or 15v
and <300mA current consumption fot the circuit.

If you need, say, 15 volts, use an LM317 type reg instead of a 7815.
Bypass the 'adj' pin to ground, 100 uF or so, and the audio-range
noise will drop by 10:1 or so. The unbypassed reference divider in a
7815 is a noise multiplier.

Not that it's likely to matter much.

John

 

[Cornholio]

The 78xx regulators work quite well actually. The important thing is
the extra filtering you do before and after the regulator. Use
quality, low ESR capacitors of adequate value. Paralleling more than
one lowers your total ESR. Use a good quality, low value ceramic in
parallel with your larger tantalums.

 

[Cornholio]

The 78xx regulators work quite well actually. The important thing is
the extra filtering you do before and after the regulator. Use
quality, low ESR capacitors of adequate value. Paralleling more than
one lowers your total ESR. Use a good quality, low value ceramic in
parallel with your larger tantalums.

 

[Steve Parus]

Linear Tech LDO have 20 microvolts noise lt1761, 1762, 1964, 1962,
1763.