[sdiy] voltage reference advice

[Paul Perry]

Well, looking at the National LM78xx series,
we have load reg of 0.3% of voltage.
And voltage tolerance of +-4% over the temperature range.

So, you can't say with much precision exactly what the voltage is going to 
be,
and even if you trim it, the voltage varies slightly (but significantly) 
with load
and possibly temperature.

I agree that for most applications this doesn't matter at all - but if you 
do need
a precise voltage, then you will need something else.

paul perry Melbourne Australia

----- Original Message ----- 
From: "Justin Owen" >
> What reasons are there for not using a decent, well-trimmed Vreg as a 
> Vref?
>
> What specs do they fall down?
>