Zener : 9 different values from 2.7V up to 30V, all from the ZPD series bar one, the 6.8V one which is a ZTK. Go figure.
The ZTY 6V8 diode is not a standard zener. It's a temperature compensated voltage reference. Basically a 6V2 zenner in series with a silicon diode. The positive temperature coefficent of the zener is cancelled by the negative of the diode.
If you check it wirh a DMM on diode check it will read open in both directions. This is because the two diodes are back to back. You have to check it in reverse with a current limited source of >7 V
It's a ZTK not ZTY. I googled but didn't find any ZTY Zener series.
Anyway the ZTK datasheet does say that it's temperature compensated, I did note that yesterday when I pulled the datasheet, but didn't know what to think of it...I mean datasheet headlines often use all sorts of buzz words to make you believe that your very common this or that part, is extra-ordinary and so much better than the others.... so I always take it with a pinch of salt.
However they don't say that it uses an extra diode in there for compensation, and indeed when I measure it, there is none. It measures just like any regular Zener.
So they must use some other kind of mechanism to achieve that compensation...
Anyway, I didn't know that there were temperature compensated Zener diodes, never mind that, at least some of them, did that by adding an extra diode in there.
So... thanks for the info !
Thanks for shouting out my typo. Maybe I should not bother replying to your posts. I don't mind being corrected but does it have to be in bold oversized font?
Wow !!!
That bad ?! You act as if I had a history of aggressing you ! I thought that rather I had always welcomed and been grateful every time you shared some of your knowledge with me !
I would have hope I would enjoy the benefit of the doubt here... oh well
Since you clearly misunderstood my intent here, and I am not at all teh evil you suggest.. I have no choice but use some bandwidth to "justify" myself and tell you what went through my mind at that time. Hopefully that will clear things up
So here goes, in chronological order, millisecond by millisecond as it unfolds in my neurons :
1) Rob gives an interesting info, as he often does, that's nice.
2) Oh, didn't know about the special Zener diodes he is talking ab out, interesting, nice of him, as per usual from him.
3) Oh, I see he is not talking about my ZTK but rather another series.
4) Cool let's go look it up and learn something.
5) Shit can't find it, bummer.
6) Maybe It's an uncommon series and I need to Google for more than 2 seconds to find it.
7) Maybe he made a typo and he meant some other series.
8 ) He can't mean the ZTK I have, because clearly it does not have a built in extra diode in there, according to the datasheet.
9) Obviously he knows that, he is the clever one here, not me.
10) I ma sure there must be lots of " Z " something series, and it's all too esy to make a typo and ruin your day.
11) If he says there is a Z series with this back to back extra diode, then I havre zero reason to doubt that, because he knows what is talking about and if he didn't, he would not have posted to tell me about these type of Zener.
12) So in conclusion, I decided to emphasize the series he is talking about so that I clear that up, and he can tell me either :
12.1) " Yes Vince, I do mean ZTY not ZTK. I am not surprised you failed to find the datasheet on a quick search because it's uncommon or obsolete and the datasheet is hard to find. But I have a copyt of it , here it is ". In which case cool I could look at the datasheet and learn more about it, and learn something.
12.2) " Oops sorry I didn't mean ZTY I mean ZAP ( or ZYB or ZUR or whatever other series that might exist out there)"... in which case I would say oh thanks, will go look it up immediately to learn more about it !
That's all there was to it really !
Back to the diode, what forward voltage does it read with a DMM on didoe test? If more than 600 mV it likely uses the series junction compension scheme. It is possible that they use two back-back junctions in series with the zener. This may be to get around patents or just a feature of how the device is constructed in silicon. Some are made using a transistor type structure.
I measure 700mV, give or take 5mV....