3 ms·

It annoys me too but part numbers are not a spec but more of a strong hint. The attitude of the industry is that it’s up to you to read data sheets carefully a

It annoys me too but part numbers are not a spec but more of a strong hint. The attitude of the industry is that it’s up to you to read data sheets carefully and test. Even for a 2N2222 or whatever.

Our_Benefactors 4mo ago
> The attitude of the industry is that it’s up to you to read data sheets carefully and test. Is this backed up by court precedent? This seems like you could easily claim damages due to a differently speccd part. I’m not doubting that’s how the industry operates, but it seems wrong so I’m curious what is supporting such a dysfunctional form of doing business.
- buescher 4mo ago
  They’re just not really standardized at all, especially semiconductors. Not in the sense you’d expect naively. Some were a long time ago, and supposedly the old Japanese sc parts were, down to die geometry and process. But otherwise, the part number means “this is like the part with a similar number first made by someone else”, not “this is an exact replacement in every way”
- ofalkaed 4mo ago
  It has worked this way since the days of the vacuum tube, so there probably is some legal precedence somewhere. I think part of this with the NE5532 is just that these days most EEs spend most of their time with digital where the data sheet and its spec is absolute; in the linear world the spec sheet is an ideal and an average because the parts themselves are an ideal and the real world never lines up with the math. Back when the NE5532 came out it was still common to see power supplies that were unregulated or barely regulated or cheap regulators with poor tolerance that would vary a fair amount with wall voltage and massive tolerances on passives, data sheets and EEs took this into account, most parts would survive max voltage but there would be a higher failure rate, so run at 70% or 80% and you don't have to worry about it. In these days of cheap SMPS and EEs that are trained with a strong lean towards digital and much improved IC fab, the max seems to be treated as the max safe voltage for good reliability and life, and you don't have to worry much about the tolerances of everything else so much. Back in the 90s when I was learning this stuff, the old EEs scolded me when ever I ran at max voltage and would patiently explain it all to me and that even if it can operate at that voltage, you can't be certain your PS will still be putting out that voltage in a year, parts drift as they age and accidents happen and the world is not ideal. They were right.
cryo32 4mo ago
MPF102 is my favourite there. “It’s a JFET” is your only guarantee. Buy binned parts and design spec spread into it.
derefr 4mo ago
Keeping in mind, though, that this is a jellybean part. You're supposed to be able to order "a" 5532 without specifying the supplier, because many vendors produce "a" 5532, and they're all the same. Different vendors' 5532s are supposed to be able to be treated as the same SKU — literally dumped into co-mingled stock in warehouses — with no ill consequence! (And yes, until TI's recent move, that was true of the 5532. All the other vendors' 5532s had matching datasheet specs, including the 22V max input voltage. Because a design that was built for "a" 5532 was usually built to run it up to 100%; and that a vendor couldn't offer their part as a swap-in if it couldn't do that.) But now, if your purchasing department (or the supplier they purchase from) happens to order TI 5532s — or if the warehouse they're sourcing from has comingled any TI 5532s into the general 5532 stock — then your product is now broken, with no real recourse except to change your entirely supply chain to one that specifically excludes TI.
- consp 4mo ago
  The EEVBlog[1] video about this has a nice example of only a single chinese manufacturer offering the same stuff as TI now does, even with the same PNP instead of NPN topology. All the others are comparable to the original. 1: https://youtu.be/22ZmmZ67SMY https://youtu.be/22ZmmZ67SMY
  - rbanffy 4mo ago
    Would be nice to call it a 5532a or something like that.
- Throwthrowbob 4mo ago
  Dave Jones also did some videos on the LMV321 used in his uCurrent Gold project. The AS5X variant caused issues while others worked fine. Looking now, a document source suggests the AS5X variant in the parts list... but it's explained in the video around 19:30 https://www.youtube.com/watch?v=1VlKoR0ldIE https://www.youtube.com/watch?v=1VlKoR0ldIE
- RetroTechie 4mo ago
  > Different vendors' 5532s are supposed to be able to be treated as the same SKU — literally dumped into co-mingled stock in warehouses — with no ill consequence! That may be true for a small webshop or a brick-and-mortar electronics store (what few of those still exist). Or be true for end users / manufacturers of equipment that includes such a part. But (afaik) that's not how it works for large reputable distributors like Mouser, Digikey & co. You don't order a generic "5532" there, you order a 5532 from <specified manucturer> there. Part from manufacturer A may, or may not be interchangeable with same-numbered part from manufacturer B. There's even some parts that have same # but very different function between manufacturers. In other words: buyers, designers do your homework. Likewise in a design, if you specify "5532" that should read as "any manufacturer's 5532 should do". If not (or unsure / untested), one should specify the part including its manufacturer. Or a list of acceptable manufacturer/part# combo's. Ofcourse changing the spec significantly for a jellybean part like discussed here (and one with many 2nd sources), that's just evil. Change a part like that, give it its own part #.
CamperBob2 4mo ago
Specs are just that... specs. A 7400 is one thing, but if you designed a circuit that barely avoids oscillating with a 10 MHz GBW, an unsolicited "upgrade" to the opamp that raises its GBW to 12 MHz may be more of a disaster than a favor. Frankly it's not OK to "upgrade" plain old TTL parts, either, since a faster 7400 might expose a race condition that never caused problems before, or cause EMI problems that didn't exist before.

Our_Benefactors 4mo ago

> The attitude of the industry is that it’s up to you to read data sheets carefully and test. Is this backed up by court precedent? This seems like you could easily claim damages due to a differently speccd part. I’m not doubting that’s how the industry operates, but it seems wrong so I’m curious what is supporting such a dysfunctional form of doing business.

buescher 4mo ago
They’re just not really standardized at all, especially semiconductors. Not in the sense you’d expect naively. Some were a long time ago, and supposedly the old Japanese sc parts were, down to die geometry and process. But otherwise, the part number means “this is like the part with a similar number first made by someone else”, not “this is an exact replacement in every way”
ofalkaed 4mo ago
It has worked this way since the days of the vacuum tube, so there probably is some legal precedence somewhere. I think part of this with the NE5532 is just that these days most EEs spend most of their time with digital where the data sheet and its spec is absolute; in the linear world the spec sheet is an ideal and an average because the parts themselves are an ideal and the real world never lines up with the math. Back when the NE5532 came out it was still common to see power supplies that were unregulated or barely regulated or cheap regulators with poor tolerance that would vary a fair amount with wall voltage and massive tolerances on passives, data sheets and EEs took this into account, most parts would survive max voltage but there would be a higher failure rate, so run at 70% or 80% and you don't have to worry about it. In these days of cheap SMPS and EEs that are trained with a strong lean towards digital and much improved IC fab, the max seems to be treated as the max safe voltage for good reliability and life, and you don't have to worry much about the tolerances of everything else so much. Back in the 90s when I was learning this stuff, the old EEs scolded me when ever I ran at max voltage and would patiently explain it all to me and that even if it can operate at that voltage, you can't be certain your PS will still be putting out that voltage in a year, parts drift as they age and accidents happen and the world is not ideal. They were right.

cryo32 4mo ago

MPF102 is my favourite there. “It’s a JFET” is your only guarantee. Buy binned parts and design spec spread into it.

derefr 4mo ago

Keeping in mind, though, that this is a jellybean part. You're supposed to be able to order "a" 5532 without specifying the supplier, because many vendors produce "a" 5532, and they're all the same. Different vendors' 5532s are supposed to be able to be treated as the same SKU — literally dumped into co-mingled stock in warehouses — with no ill consequence! (And yes, until TI's recent move, that was true of the 5532. All the other vendors' 5532s had matching datasheet specs, including the 22V max input voltage. Because a design that was built for "a" 5532 was usually built to run it up to 100%; and that a vendor couldn't offer their part as a swap-in if it couldn't do that.) But now, if your purchasing department (or the supplier they purchase from) happens to order TI 5532s — or if the warehouse they're sourcing from has comingled any TI 5532s into the general 5532 stock — then your product is now broken, with no real recourse except to change your entirely supply chain to one that specifically excludes TI.

consp 4mo ago
The EEVBlog[1] video about this has a nice example of only a single chinese manufacturer offering the same stuff as TI now does, even with the same PNP instead of NPN topology. All the others are comparable to the original. 1: https://youtu.be/22ZmmZ67SMY https://youtu.be/22ZmmZ67SMY
- rbanffy 4mo ago
  Would be nice to call it a 5532a or something like that.
Throwthrowbob 4mo ago
Dave Jones also did some videos on the LMV321 used in his uCurrent Gold project. The AS5X variant caused issues while others worked fine. Looking now, a document source suggests the AS5X variant in the parts list... but it's explained in the video around 19:30 https://www.youtube.com/watch?v=1VlKoR0ldIE https://www.youtube.com/watch?v=1VlKoR0ldIE
RetroTechie 4mo ago
> Different vendors' 5532s are supposed to be able to be treated as the same SKU — literally dumped into co-mingled stock in warehouses — with no ill consequence! That may be true for a small webshop or a brick-and-mortar electronics store (what few of those still exist). Or be true for end users / manufacturers of equipment that includes such a part. But (afaik) that's not how it works for large reputable distributors like Mouser, Digikey & co. You don't order a generic "5532" there, you order a 5532 from <specified manucturer> there. Part from manufacturer A may, or may not be interchangeable with same-numbered part from manufacturer B. There's even some parts that have same # but very different function between manufacturers. In other words: buyers, designers do your homework. Likewise in a design, if you specify "5532" that should read as "any manufacturer's 5532 should do". If not (or unsure / untested), one should specify the part including its manufacturer. Or a list of acceptable manufacturer/part# combo's. Ofcourse changing the spec significantly for a jellybean part like discussed here (and one with many 2nd sources), that's just evil. Change a part like that, give it its own part #.

CamperBob2 4mo ago

Specs are just that... specs. A 7400 is one thing, but if you designed a circuit that barely avoids oscillating with a 10 MHz GBW, an unsolicited "upgrade" to the opamp that raises its GBW to 12 MHz may be more of a disaster than a favor. Frankly it's not OK to "upgrade" plain old TTL parts, either, since a faster 7400 might expose a race condition that never caused problems before, or cause EMI problems that didn't exist before.