Regulator Noise

[Paul Schreiber]

In my "day job" I was looking at the LM78xx series versus the even older LM723. Much to my surprise, I found
(or re-remembered from my Model 1/CoCo days!!!) that:

1) The LM723 has 100 TIMES better ripple rejection
2) Has 10 TIMES better load regulation
3) Has 5 TIMES better line regulation

and is the same price or cheaper!!! I bought 50 SGS parts for $0.24ea.

Now, it is good to 100ma before you add a $0.12 pass transistor. Then you can get 1-3A.

Lastly, it can withstand 40V of input versus 30V for the 78xx. This is a very important factor in using 24VAC 
inputs, like I have to.

Sometimes, the "simple" solution isn't the best. And 100ma will drive about 8 CEM chips and 4 quad op amps.

Paul Schreiber
Synthesis Technology