Are these USB series resistors important?

[tggzzz]

Stupid would be dropping the parts when you know they are required.  The OP's question was whether they are required or not. 

Stupid is also asserting that parts can be dropped without knowing why they are there.

Classic straw man argument.  The OP never asserted that the series resistors can be dropped.  That is obvious from the subject, "Are these USB series resistors important?"

Can you point to where I made that assertion? If not, yours is the classic straw man argument!

[zapta]

Can you point to where I made that assertion? If not, yours is the classic straw man argument!

tggzz, any suggestion for a small USB protection filter that has ~33 ohm resistors and no hard wired 1.5K pullup resistor?

[tggzzz]

Can you point to where I made that assertion? If not, yours is the classic straw man argument!

tggzz, any suggestion for a small USB protection filter that has ~33 ohm resistors and no hard wired 1.5K pullup resistor?

Que?

That is your second strawman argument!

Can I suggest reading a little more slowly and waiting 5 minutes before clicking the "Post" button.

[zapta]

tggzz, any suggestion for a small USB protection filter that has ~33 ohm resistors and no hard wired 1.5K pullup resistor?

Que?

That is your second strawman argument!

Can I suggest reading a little more slowly and waiting 5 minutes before clicking the "Post" button.
[/quote]

[ralphd]

Stupid is also asserting that parts can be dropped without knowing why they are there.

Classic straw man argument.  The OP never asserted that the series resistors can be dropped.  That is obvious from the subject, "Are these USB series resistors important?"

Can you point to where I made that assertion? If not, yours is the classic straw man argument!

It's right there above, "Stupid is also asserting that parts can be dropped without knowing why they are there."  Unless the forum software is screwed up, those are your words.

You misrepresent the OP by implying he's asserting parts can be dropped by without knowing why they are there, then you knock it down as being stupid.
A straw man argument is when you build a straw man to represent your opponent, and then knock it down.  The typical motivation is that you can't criticize the opponents actual position, so create a proxy for your opponent which you criticize instead.

[tggzzz]

Stupid is also asserting that parts can be dropped without knowing why they are there.

Classic straw man argument.  The OP never asserted that the series resistors can be dropped.  That is obvious from the subject, "Are these USB series resistors important?"

Can you point to where I made that assertion? If not, yours is the classic straw man argument!

It's right there above, "Stupid is also asserting that parts can be dropped without knowing why they are there."  Unless the forum software is screwed up, those are your words.

You misrepresent the OP by implying he's asserting parts can be dropped by without knowing why they are there, then you knock it down as being stupid.
A straw man argument is when you build a straw man to represent your opponent, and then knock it down.  The typical motivation is that you can't criticize the opponents actual position, so create a proxy for your opponent which you criticize instead.

Please re-read the statements and point out where I asserted that the OP said the resistors could be dropped. The OP didn't say that, and I didn't assert they had. Hence your statement "The OP never asserted that the series resistors can be dropped" was strawman statement.

[wraper]

Stupid is also asserting that parts can be dropped without knowing why they are there.

Classic straw man argument.  The OP never asserted that the series resistors can be dropped.  That is obvious from the subject, "Are these USB series resistors important?"

Can you point to where I made that assertion? If not, yours is the classic straw man argument!

It's right there above, "Stupid is also asserting that parts can be dropped without knowing why they are there."  Unless the forum software is screwed up, those are your words.

You misrepresent the OP by implying he's asserting parts can be dropped by without knowing why they are there, then you knock it down as being stupid.
A straw man argument is when you build a straw man to represent your opponent, and then knock it down.  The typical motivation is that you can't criticize the opponents actual position, so create a proxy for your opponent which you criticize instead.

Aren't you a politician by the way? You seem to have a good talent to misrepresent the words other people have said and slap your straw argument on top of that. I don't see tggzzz mentioning OP and particular situation with resistors at all. Sorry for the long quotations but they are needed to show what you call straw arguments.

The pride of doing it right as opposed to slap it together

And some people take pride in efficiency/minimalism.  Waste not want not...

And in result making devices which are waste by themselves. IMO one can have pride about minimalism only if find how to achieve the same thing in some smart way that requires less parts. Not stupidly cutting "unnecessary" parts.

Most of economics/business comes down to doing more with less.  While over-engineering makes sense for transportation or medical devices, for consumer devices it is the minimalist designs that succeed.

You seem to have a rather big ego to equate the suggestion of dropping the series resistors with stupidly cutting parts.
Stupid would be dropping the parts when you know they are required.  The OP's question was whether they are required or not.  I think it is stupid to assert that they are required without having tested the circuit or at least a similar one.

Show where I said that dropping resistors is stupid? I made a comment about pride doing things well in elegant way, not about dropping resistors. I only see that you try to insult others in your comments, particularly:

You seem to have a rather big ego to equate the suggestion of dropping the series resistors with stupidly cutting parts.

Show me please where I was "equating" something with something.

[tggzzz]

I'm going to pigeonhole ralphd as a troll, and cease trading points with him. Others are free to take a different view, of course.

[paulie]

"Pride" seems to be the main theme here for several of the opposing team. As though it's an essential ingredient of good engineering. There are other words for it and BTW consider that in western (christian) and other religions it's one of The Seven Deadly Sins. I'm not religious but IMO economy and efficiency play a far more important role.

I see 2 warring factions: the "professionals" who try to throw out as many buzz words and irrelevant technical issues to cloud the issues and generally show how smart they are. Then there's the "git 'er done (and git 'er done cheap)" hobby dudes who just want to build something and have fun. The former seem to harbor great resentment over this and tend to jump up and down and harass at every opportunity.

Fortunately this is the internet and there's not much they can actually do about it. For example if I were designing Worlds Smallest Arm for personal amusement those 33R resistors would be the first things to go. No caps on the crystal either. And guess what... I'M LEAVING OUT BYPASS CAPS TOO !!! And the board still works. I do know what these things are for but gonna yank 'em anyway.

So nya... nya... nya... how about that windbags?  LOL.

(ps. It is kinda funny to see them turning on each other when they run out of noobs to pummel)

[luky315]

When you're done with your "discussion":
The STF202 from On Semi is a all in one USB input protection with integrated resistors.
It works fine and is big enough (0,95mm pitch) for amateur soldering.

[zapta]

When you're done with your "discussion":
The STF202 from On Semi is a all in one USB input protection with integrated resistors.
It works fine and is big enough (0,95mm pitch) for amateur soldering.

Thanks for the pointer. I need one that doesn't have a hard wired pullup resistor. This is because the board needs to be re-enumerated when it changes USB profile (e.g. from serial CDC to virtual disk).

BTW, the pullup signaling is done on the D+ signal. Will it work if I will use the STF202 with the fixed pullup on the D- signal and adding my own switched pullup on the D+?

[retrolefty]

"Pride" seems to be the main theme here for several of the opposing team. As though it's an essential ingredient of good engineering. There are other words for it and BTW consider that in western (christian) and other religions it's one of The Seven Deadly Sins. I'm not religious but IMO economy and efficiency play a far more important role.

I see 2 warring factions: the "professionals" who try to throw out as many buzz words and irrelevant technical issues to cloud the issues and generally show how smart they are. Then there's the "git 'er done (and git 'er done cheap)" hobby dudes who just want to build something and have fun. The former seem to harbor great resentment over this and tend to jump up and down and harass at every opportunity.

Fortunately this is the internet and there's not much they can actually do about it. For example if I were designing Worlds Smallest Arm for personal amusement those 33R resistors would be the first things to go. No caps on the crystal either. And guess what... I'M LEAVING OUT BYPASS CAPS TOO !!! And the board still works. I do know what these things are for but gonna yank 'em anyway.

So nya... nya... nya... how about that windbags?  LOL.

(ps. It is kinda funny to see them turning on each other when they run out of noobs to pummel)

 But it's those various flavors that make this forum so entertaining for many of us. It's not just about education you know. The various xxx-nuts threads can entertain for months and years.

[Pjotr]

Yeah, but lengthy quibbling about just 2 resistors costing a fraction of a cent? By hell, what are that pro EE's supposed to design? The hobbyists do it and find their own way anyway

[free_electron]

"Pride" seems to be the main theme here for several of the opposing team. As though it's an essential ingredient of good engineering. There are other words for it and BTW consider that in western (christian) and other religions it's one of The Seven Deadly Sins. I'm not religious but IMO economy and efficiency play a far more important role.

I see 2 warring factions: the "professionals" who try to throw out as many buzz words and irrelevant technical issues to cloud the issues and generally show how smart they are. Then there's the "git 'er done (and git 'er done cheap)" hobby dudes who just want to build something and have fun. The former seem to harbor great resentment over this and tend to jump up and down and harass at every opportunity.

Fortunately this is the internet and there's not much they can actually do about it. For example if I were designing Worlds Smallest Arm for personal amusement those 33R resistors would be the first things to go. No caps on the crystal either. And guess what... I'M LEAVING OUT BYPASS CAPS TOO !!! And the board still works. I do know what these things are for but gonna yank 'em anyway.

So nya... nya... nya... how about that windbags?  LOL.

(ps. It is kinda funny to see them turning on each other when they run out of noobs to pummel)

and the board may very well work apart from sometimes random resetting , locking up , doing strange things, not working on some computers , disconnecting itself, reconnecting random re-enumerating.
but we can blame that on windows and crappy software right ...

while we are at it. why don't you just remove the locks from your doors , they are not necessary. anyone who wants to enter your house will ram the door, drill the lock or smash the window anyway.

[zapta]

while we are at it. why don't you just remove the locks from your doors , they are not necessary. anyone who wants to enter your house will ram the door, drill the lock or smash the window anyway.

That's a very good example. There is a wide spectrum of home safety equipment and each household pick whatever fits them. I would expect that this would be the same with securing (need a better word) electronic designs. That is, it's not necessarily one size fits all. Same goes to design processes, assembly environment (e.g. ESD), EMI, USB impedance matching and so on.

I would like to hear from the pros here, do you always design with the same level of protection or does it 'depend'?

[tggzzz]

I would like to hear from the pros here, do you always design with the same level of protection or does it 'depend'?

You assess the threats and relative threats. You assess methods of mitigating the threats, and their costs. You make a cost-benefit tradeoff.

Sometimes you get it wrong; the Ford Pinto being the classic example.

I have several times realised during my journey to work that I hadn't shut the front door. I didn't bother to go back and close it. There were no problems.

I have occasionally deliberately left the front door open, when I judged the risk from having it locked was worse than the risk of leaving it open.

[luky315]

@zapta:
I don't know a protection device without the pullup resistor in a "solder freindly" package. There is the NUF2042 from On Semi, but it's in a 1.2mm x 1.6mm SOT?563 with 0.5mm pitch... Not a real problem if you go into production, but a challenge for hand soldering.

[zapta]

@zapta:
I don't know a protection device without the pullup resistor in a "solder freindly" package. There is the NUF2042 from On Semi, but it's in a 1.2mm x 1.6mm SOT?563 with 0.5mm pitch... Not a real problem if you go into production, but a challenge for hand soldering.

Luky315, I just finalized the design with nuf2042 and sent to oshpark. It's about the same pitch as the MCU so I should be able to solder it. The only issue is that the resistors are 22 ohm and not 33 as the MCU's datasheet recommend but should be better than zero.

[paulie]

But it's those various flavors that make this forum so entertaining for many of us. It's not just about education you know. The various xxx-nuts threads can entertain for months and years.

Sometimes entertaining, other times plain sad. At least from my viewpoint.

Admittedly I learned a lot in those LM399 and LT2000 threads. Not just electronics but physics and science in general. But then the blood fest started with that Jesus freak Ebay seller. Ironically several (not just one or two) initial reviews showed his product performed more than 10x better than it was supposed to. Very disappointing to see "upper echelon" individuals I had great respect for take part in the lynching. Maybe the same personality defect responsible for this behavioral quirk goes hand in hand with ability to innovate and think outside the box so.... I dunno.