Gate protection zeners are much more common in the more modern, higher-performance parts. So if you are used to using dinosaurs, you might think they're rare. Also, manufacturers occasionally get sloppy about noting their existence; you really need to see an I_GSS spec to be sure. (And because, well, if you're concerned about gate leakage, that is the spec!)
The 2N7000 is significantly worse than other MOSFETs. I don't know if that's because it's older, because its fab process is worse or was worse at one time, because it's easy to get those TO-92 legs into trouble, or just because of the die's low C_iss, but it's one fragile little bastard. The 2N7002 seems to be much better!
> Unprotected MOSFETs have nothing to do with "old" or "new".
Yes, they do, because the 2N7000 is older (1986) than integrated gate protection devices! Anything you see with them isn't a "true" 2N7000, even if it might meet the JEDEC spec sheet (which is rather hard to turn up...). Modern versions might have protection or might not (check the letters at the end of the part number... and hope you've got the right era of datasheet... and hope you've got the original MPN and don't have to read the condensed markings on the parts themselves... oh and hope you know the actual manufacturer!), but if they're older then they certainly won't have protection. So it kind of is an old (nope) versus new (maybe) thing.
> You can't just replace unprotected MOSFETs with protected ones and hope that your circuits work. You very well could be shorting out some circuit inadvertently.
Okay, technically, yes. In practice, no. Enhancement MOSFETs are usually used for power/switching applications, which won't care one damn bit about a silly diode, or in feedback loops for analog applications, which again won't care much. For various reasons, JFETs and depletion MOSFETs are usually preferred in analog-land, along of course with ICs. That's not to say you don't see discrete enhancement MOSFETs, but it's very, very uncommon. (And when I try to design that sort of stuff, I always seem to get stuck on not being able to find a FET without the pesky diodes built in. Sigh.)
August 2022 part. Unprotected MOSFET. Top-of-the-line, modern technology with 0.003 Ohms Rds, 157 Amps supported.
Protected vs unprotected has nothing to do with old or new. And yes, the specs on the 2N7000 suck, but who cares? It gets the job done and is the dirt-cheapest part. Beginners don't need performance, they just need lots of parts to play with, so cheapness probably takes priority.
> Also, manufacturers occasionally get sloppy about noting their existence
What are you talking about?
Any MOSFET with ESD-protection has a Human-body model (HBM) ESD specification. Probably in the realm of 2000V, or +/-1700V, depending on how the protection diode works.
TI btw makes a ton of ESD-protected MOSFETs with 4000V ESD and like 50nA of leakage. But they're much costlier, and of course surface-mount only because that's what pros use in practice. (Beginners definitely prefer through hole so that it works on breadboards, which is another reason to use 2N7000).
The 2N7000 is significantly worse than other MOSFETs. I don't know if that's because it's older, because its fab process is worse or was worse at one time, because it's easy to get those TO-92 legs into trouble, or just because of the die's low C_iss, but it's one fragile little bastard. The 2N7002 seems to be much better!
> Unprotected MOSFETs have nothing to do with "old" or "new".
Yes, they do, because the 2N7000 is older (1986) than integrated gate protection devices! Anything you see with them isn't a "true" 2N7000, even if it might meet the JEDEC spec sheet (which is rather hard to turn up...). Modern versions might have protection or might not (check the letters at the end of the part number... and hope you've got the right era of datasheet... and hope you've got the original MPN and don't have to read the condensed markings on the parts themselves... oh and hope you know the actual manufacturer!), but if they're older then they certainly won't have protection. So it kind of is an old (nope) versus new (maybe) thing.
> You can't just replace unprotected MOSFETs with protected ones and hope that your circuits work. You very well could be shorting out some circuit inadvertently.
Okay, technically, yes. In practice, no. Enhancement MOSFETs are usually used for power/switching applications, which won't care one damn bit about a silly diode, or in feedback loops for analog applications, which again won't care much. For various reasons, JFETs and depletion MOSFETs are usually preferred in analog-land, along of course with ICs. That's not to say you don't see discrete enhancement MOSFETs, but it's very, very uncommon. (And when I try to design that sort of stuff, I always seem to get stuck on not being able to find a FET without the pesky diodes built in. Sigh.)