Re: Source for low current zener in China?

Hello Robert,


Problem is, when I detect excessive impedance and ask the mfgs about it they seem to become silent. Hmm....

So how come this thing has worked in the past? (You said it was a legacy
design so I assume it has been successfully in production for a while.)


Well over a decade without problems.


Were those real "low-current zeners" that all of a sudden have gone to
the land of unobtainium, or did the finished product work only by sheer
luck in the high-impedance knee region of whatever diodes were designed
in back then?


Not by luck. The design is within data *** limits. The low cutoff is what matters. Data *** says it's between 5.32V and 5.88V at 50uA. We run at 200uA and had a lot of them below our cutoff limit of 5.1V. Oops! So I wrote, asking about whether it could be a lot glitch. No call back so far...

--
Regards, Joerg

http://www.analogconsultants.com
.