Bootstrapped Zener reference

[badeez at mail.colba.net]

Hi everybody,

I've come across several problems recently with this cct
(SH-101 psu) as it seems to be a favourite of Roland. JP-6 has it 
as well.

It provides for a very stable reference voltage (temperature 
compensated) with ordinary 4558 op-amp and lo drift zener.

For more info on this circuit check out the classic
"IC Op-Amp Cookbook"  third edition by Walter Jung
page 188 .

If anyone is having a hard time locating a 1SZ46A 6.4V zener(NEC)
try subbing a 1N4565 6.2V(Motorola) instead,and adjust for the
difference with VR1 (SH-101 cct around IC1-b).

So,if you've got a spare op-amp left over in your design and 
need a stable  Vref ,don't run out and buy the latest 3 terminal
varieties,get the zener and a couple of 1% metal film resistors
and voila !


Tony Kalomiris
IC1 Electronics
badeez at colba.net