LM431

mikep · Dec 12, 2006

has anyone used this part? looks interesting. I wonder how low the noise is in real life. it is pretty cheap.

edit: It is an adjustable precision shunt regulator TO-92 package, just enough current/dissipation to power minimal circuitry directly or together with a BJT for more current or to make a CCS.

mike p

clintrubber · Dec 12, 2006

I guess it's the same as a TL431, right ?

If indeed so then there's a Jensen-circuit using it,
see:

http://www.groupdiy.com/index.php?topic=19025&highlight=phantom+test+jensen

Regards,

Peter

bcarso · Dec 12, 2006

Svart has had a lot of problems with it, although I've generally found it to do what it says. Beware of the capacitive loading vs. stability---see the charts in the datasheet.

Svart · Dec 12, 2006

It can be a touchy bugger sometimes but looking back I think the problems have been more in the overall designs that allow it to give you problems.

Man I'm starting to sound soft.. :roll:

Some of their tempco shifts were pretty bad as I remember. Try to factor that into your design. I've seen too many designs lately go haywire due to the lack of tempco foresight..

Damn the RF world.

:green:

mikep · Dec 14, 2006

[quote author="Svart"]

Some of their tempco shifts were pretty bad as I remember. Try to factor that into your design. [/quote]

ooh. it was the suposedly small tightly controlled tempco that attracted me to the part! that and the low noise. I was thinking of using it instead of a zener for a bias generator and as a simple regulator to run one 36V IC in an otherwise higher-rail (discrete) system.

Svart · Dec 14, 2006

If the part is from a known manufacturer and the specs are well defined it probably won't have any problems. However my experience with the part type was mainly that of extremely low cost, foreign origin parts. I would trust a TI part but not one of an unknown, likely chinese knockoff, origin that we usually see in extremely cheap switchers.

I guess the moral is the same as any other part, use well known manufacturers and parts and you'll likely be safe.

bcarso · Dec 14, 2006

Yes, if from a good manufacturer who is maintaining quality assurance, they are usually pretty decent. They are based on a bandgap topology which can be quite low TC.