Do semiconductor datasheets suck?

[magic]

Not hard to find examples; https://www.ti.com/lit/ds/symlink/cd4011b.pdf perhaps surprising that it's not been updated for such a basic datasheet, when others have (4013 for example).

You win, I guess.

But it says "acquired from Harris Semiconductor" so maybe TI never had this document in any sensible digital format and can't be bothered to recreate it.


And by the way, I'm no TI fanboy and their datasheets aren't exactly perfect. When they came up with "recommended operating conditions" they retroactively added them to most existing datasheets, usually something generic like "±15V supply" for opamps, regardless of actual abilities of given model. They shuffle sections around and occasionally mess something up, like the OP07 which had its schematic replaced with a 741 during datasheet overhaul. There are datasheets like TL431 consisting of numerous copy-pasted tables differing in a few digits here and there. There is the TL072H shoved into TL072 datasheet even though all its specs are separate from the latter.

[David Hess]

If block diagrams are given, then input and output circuits should be shown in detail.
The test circuits used to measure parameters should be published.

Depending on the product, yes. Older op-amps TI/NatSemi used to show the transistor level design, but even this was sanitized.  More complex products that would be a negative, Ghost Rider. That ESD clamp? We show a Zener, but it's not really a Zener. It simply acts as one. We would not show the logic on how PFM mode is activated in a buck converter mode pin; there would simply be a "PFM Logic" block. It's simply too complex.

When required, simplified schematics are usually good enough, and often better because they are easier to follow.  For instance they are indispensable when understanding what clamp, compensation, and offset null pins do in operational amplifiers.

For some newer operational amplifiers from Texas Instruments, it is impossible to know the differential input range because there is no input schematic, and the specifications either do not say or are conflicting.  And which way does the input bias current flow?  You just have to measure it.

And by the way, I'm no TI fanboy and their datasheets aren't exactly perfect.

It is not a matter of being perfect.  In the past Texas Instruments sometimes misled or deliberately lied on their datasheets.  When you read the articles from Bob Pease talking about someone publishing misleading datasheets, he is referring to Texas Instruments.

[schmitt trigger]

Not hard to find examples; https://www.ti.com/lit/ds/symlink/cd4011b.pdf perhaps surprising that it's not been updated for such a basic datasheet, when others have (4013 for example).

But it says "acquired from Harris Semiconductor" so maybe TI never had this document in any sensible digital format and can't be bothered to recreate it.

This datasheet has a long lineage.

I still have an original RCA COS/MOS data book, published on 1980, and the TI datasheet posted by T3sl4co1l is identical to the one on my book.

Harris acquired it from RCA Semi, via a brief detour from GE, and I believe Intersil.

[magic]

For some newer operational amplifiers from Texas Instruments, it is impossible to know the differential input range because there is no input schematic, and the specifications either do not say or are conflicting.  And which way does the input bias current flow?  You just have to measure it.

TI's new precision bipolar opamps seem to use bias cancellation.
Maybe it's different with the cheaper LMVxxx stuff.

[Kleinstein]

There is the TL072H shoved into TL072 datasheet even though all its specs are separate from the latter.

The mess with TL072H is not just a data sheet problem. It starts with naming that is causing more confusion than good.  It is still another bad step to have a combined datasheet, as the old TL072 and new CMOS TL072H have not much in common. Not hat the TL072H is a bad part, it just got a bad name.
Combined datasheets that handle multiple parts are often a good thing, if the parts are really the same core  (e.g. 1/2/4 fold OP-amps or different voltage regulators).

For the OP-amps it would be good if they directly write if the use bias compensation or not. At least the newer DS give the signs and one finds out.

The main 2 points where I have seen repeatedly wrong values is with the current noise of AZ OP-amps and the DC SOA of MOSFETs. The wrong SOA curves are especially nasty, as this can (but one may be "lucky" with a prototype) cause failures that cause additional damage.

[T3sl4co1l]

There is the TL072H shoved into TL072 datasheet even though all its specs are separate from the latter.

The mess with TL072H is not just a data sheet problem. It starts with naming that is causing more confusion than good.  It is still another bad step to have a combined datasheet, as the old TL072 and new CMOS TL072H have not much in common. Not hat the TL072H is a bad part, it just got a bad name.
Combined datasheets that handle multiple parts are often a good thing, if the parts are really the same core  (e.g. 1/2/4 fold OP-amps or different voltage regulators).

For the OP-amps it would be good if they directly write if the use bias compensation or not. At least the newer DS give the signs and one finds out.

The main 2 points where I have seen repeatedly wrong values is with the current noise of AZ OP-amps and the DC SOA of MOSFETs. The wrong SOA curves are especially nasty, as this can (but one may be "lucky" with a prototype) cause failures that cause additional damage.

This is probably the most egregious example, being same-source.

Similar hazards can be found with new substitutes from other companies.  A recent one that comes to mind:
http://file.3peakic.com.cn:8080/product/Datasheet_LM2903A-LM2901A.pdf
The things that most jump out to me are:
- Input bias current is greatly improved
- Output current and saturation voltage are improved
- Response time is a little slower
- Waveforms are far too symmetrical: response time looks like a double-pole CMOS amp (decomp'd, of course), output is clearly CMOS type
- Input ESD diodes include supply (original allowed "over the top" inputs!)

It's a lie; it's definitely a completely different type, design, architecture.  It does look pretty good, in and of itself -- aside from the somewhat slower response, I don't have any particular problems with its specs, though it would be nice to have more performance graphs.  They also specify input reversal conditions (one input beyond Vicm still gives correct result; both outside, indeterminate).  It's literally just one thing: an LM2901/3A, it is not!

I had looked at a few other products of theirs, I think which seem alright mostly, but catches like this can be as simple as tripping up the less-careful employees in purchasing.

Tim

[magic]

There are similar LM358 coming from China too.
It will be particularly "fun" when it breaks and somebody replaces it with the original part, but the design relied on lower bias or something.

Thankfully, nobody repairs anything anymore

[T3sl4co1l]

There are similar LM358 coming from China too.
It will be particularly "fun" when it breaks and somebody replaces it with the original part, but the design relied on lower bias or something.

Thankfully, nobody repairs anything anymore

Or relies on the class C output stage to...

wait.

([further?] implying that random CMOS versions are likely to be, if not universally, then in most respects, a strict improvement upon the original)

Tim

[coppice]

There are similar LM358 coming from China too.
It will be particularly "fun" when it breaks and somebody replaces it with the original part, but the design relied on lower bias or something.

Thankfully, nobody repairs anything anymore

This happens all the time. None of the look alike parts work exactly like the originals. Usually they work a little better than the original, as they were designed not to cause trouble as a substitute. If you design and test around the second source part, the original may cause some nasty surprises. The snag is often trying to find which of the alternatives has the worst spec in its data sheet, so you can design around that.

[VK3DRB]

Most Chinese datasheets suck. Missing key information in almost every datasheet, but providing useless manufacturing inspection pass/fail criteria. You have to contact the Chinese manufacturers to get the info you need. Recently, after asking for 3D step files and pricing for a connector, the female sales person hunted my phone number down on WhatsApp and seem to want to set up a relationship as friends. Not bloody interested, I don't care how pretty she looked. I just want data, not a date.

American datasheets are pretty good generally. But not long ago I found a subtle bug in a Texas Instruments datasheet where they had cut and pasted info from another datasheet and forgot to change the data. Just this week, I found TI has been shipping a certain IC with the WRONG part number on them. One of the recipients has been Mouser. The chips don't work because they are in fact a different part! TI has quality assurance problems which seem to have been getting worse in recent times. Lets' hope things improve within TI.

Worst American datasheets by far are Honeywell sensor datasheets. Wrong data causing fatal damage to the device when used as instructed. A company that has no competent documentation QA. Sensirion is a far safer company to use and they have excellent datasheets and sensors.

[EPAIII]

Well, I have lived in the US for almost 80 years and this is the first time I have heard that one.

Way back in elementary school I do remember one of my teachers telling the class that you should ALWAYS explain what an acronym means the first time you use it in any place. It is just common courtesy.

May I propose one more rule of thumb?

EILI5

Avoid acronyms unless they are really standard terminology. If you have to use them, define them. 
I had to Google that one. Maybe it's a common meme in the US, but I had not come across it.

[tooki]

I’m American too and I’ve never seen that acronym before, either. I don’t think it’s very common.

[magic]

It's reddit slang, which means not knowing it is probably a good thing. Too late for me

[VK3DRB]

Well, I have lived in the US for almost 80 years and this is the first time I have heard that one.

Way back in elementary school I do remember one of my teachers telling the class that you should ALWAYS explain what an acronym means the first time you use it in any place. It is just common courtesy.

May I propose one more rule of thumb?

EILI5

Avoid acronyms unless they are really standard terminology. If you have to use them, define them. 
I had to Google that one. Maybe it's a common meme in the US, but I had not come across it.

It's not an acronym. It is an initialism. Know the difference.

Datasheets generally appropriately use acronyms and initialisms if they are from a reputable company like Analog Devices and many others. Know your audience. IBM overdid abbreviations to the extreme without necessarily defining them. I know because I worked there for 18 years.

I do find the excessive use of initialisms and acronyms in embedded code or net labels on schematics, incredibly annoying, especially when some "programmer" or "engineer" with tunnel vision decides to run them together. One can only assume people do this out of laziness, incompetence, or to protect their employment.

Now SDA and SCL are fine, because the audience should know what they are. Because most datasheets refer to the Philips (NXP) I²C standard.

I have spent the last three months ploughing through a maze of embedded code for an STM32 written by someone who didn't know how to write code properly. One intermittent bug took me about two weeks to find. If the author he had written the code to be readable, I would have nailed in under two hours. It is a nightmare with many thousands of lines of gobbledegook. It is barely commented throughout. The author died in August, so there is no point asking him what or why things are done in his code.

Here are some initialisms he used: iia (index in array), idx (index) - yes he mixed the abbreviations up. sn (sensor) and sno (serial number) - ambiguous nonsense. Ready for this one? P. Oh, that means pressure and I could only work that out from the datasheet. Of course there hardly any comments, and poor and illogical code structure... it all needs to be to be rewritten.

The bottom line: You are writing code and creating a schematic primarily for other humans to read, not decode. Second to that, the code should work.

ANDDNTOVRUSEABRVS_whenHumanReadibleWordsAreSoMuchBetterEvenIn_camelCase.

[PlainName]

Datasheets generally appropriately use acronyms and initialisms if they are from a reputable company

Off-hand I can't recall a reputable datasheet using initialisms. Can you think of an example to illustrate? I may have led a sheltered life, but initialisms just don't strike me as something proper sources would use.

[thm_w]

Datasheets generally appropriately use acronyms and initialisms if they are from a reputable company

Off-hand I can't recall a reputable datasheet using initialisms. Can you think of an example to illustrate? I may have led a sheltered life, but initialisms just don't strike me as something proper sources would use.

Open a charger or DC/DC datasheet you'll probably see 10 or 20 of them: PWM, MPPT, OCP, VDD, LED, DCM, etc.

[PlainName]

Duh! You are quite right - they are everywhere and my eye just coasts straight over them 

[VK3DRB]

Datasheets generally appropriately use acronyms and initialisms if they are from a reputable company

Off-hand I can't recall a reputable datasheet using initialisms. Can you think of an example to illustrate? I may have led a sheltered life, but initialisms just don't strike me as something proper sources would use.

Open a charger or DC/DC datasheet you'll probably see 10 or 20 of them: PWM, MPPT, OCP, VDD, LED, DCM, etc.

and SCL, SDA, I2C, EIAJ, TCP/IP, SPI, I2S. they are all initialisms. UART, USART, FIFO are acronyms. EEVBLOG is a hybrid of an initialism and plain text. Its academic, but we all know what we mean. One thing I do frown on is when an engineer or technician who might say "50 Hertz" also says something like "It is one Hert off". I have heard this a few times over the decades. I don't want to hurt Mr. Hert too much, so usually I just gently tell him he is first class submoron

[CatalinaWOW]

Datasheets generally appropriately use acronyms and initialisms if they are from a reputable company

Off-hand I can't recall a reputable datasheet using initialisms. Can you think of an example to illustrate? I may have led a sheltered life, but initialisms just don't strike me as something proper sources would use.

Open a charger or DC/DC datasheet you'll probably see 10 or 20 of them: PWM, MPPT, OCP, VDD, LED, DCM, etc.

and SCL, SDA, I2C, EIAJ, TCP/IP, SPI, I2S. they are all initialisms. UART, USART, FIFO are acronyms. EEVBLOG is a hybrid of an initialism and plain text. Its academic, but we all know what we mean. One thing I do frown on is when an engineer or technician who might say "50 Hertz" also says something like "It is one Hert off". I have heard this a few times over the decades. I don't want to hurt Mr. Hert too much, so usually I just gently tell him he is first class submoron

And he might return in kind because the usage was intentional punnage.  Last word chosen to annoy language purists.

[TimFox]

Here is the list of accepted abbreviations (mostly initialisms) allowed for publication in American Institute of Physics (AIP) scientific journals without further definition:
https://www.carleton.edu/physics-astronomy/major/integrative-exercise/comps/style-manual/appedix-d/
Otherwise, in scientific publications, the abbreviation should be spelled out on first introduction.
This made for interesting titles when 7,7,8,8 tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) was a very active research topic in the 1970s.

[shapirus]

Here's a fresh example, the one I'm reading right now.

TI's CD74HCT132: https://www.ti.com/lit/ds/symlink/cd74hct132.pdf

It's either that I don't know how to read and understand datasheets, or it has not been QA'ed and is a result of some quick copy-pasting.


section 9.2.1.2 Input Considerations

The CD74HCT132 has CMOS inputs and thus requires fast input transitions to operate correctly, as defined in
the Recommended Operating Conditions table. Slow input transitions can cause oscillations, additional power
consumption, and reduction in device reliability.

Fair enough. Now, how fast should "fast" be? Let's see the mentioned table... only to find that it does not contain any specifications on the required input transition timings.

And the very next paragraph says:

The CD74HCT132 has no input signal transition rate requirements because it has Schmitt-trigger inputs.

Of course, the Schmitt-trigger inputs are in the product title. But... why does the first paragraph that I quoted above state that the device requires fast input transitions? Looks very much like an overlooked copy-paste from another datasheet to me.


Next,

Unlike what happens with standard CMOS inputs, Schmitt-trigger inputs can be held at any valid value without
causing huge increases in power consumption. The typical additional current caused by holding an input at a
value other than V_CC or ground is plotted in the Typical Characteristics.

...unless I fail to see it there, the mentioned plots are not present in the Typical Characteristics section.


Finally,

Refer to the Feature Description section for additional information regarding the inputs for this device.

But there is no section named Feature Description (do the datasheet writers not use tools such as LaTeX that can substitute the section names, links, and page numbers dynamically, referenced by internal id?).

Additionally, there is no specification for the minimum time during which an input must be held high or low to be registered as such, whereas it is one of important characteristics of logic ICs.

This one is definitely not among the better part of the datasheets that I've ever read.

Curiously, it does contain a "submit document feedback" link. I'll try it!

[SiliconWizard]

Yes, it definitely looks like some half-baked copy-pasting from other datasheets. (And to be fair, for people who have written many datasheets, who has never done that, and forgot to adapt/remove some sentences that would not apply?)
Reviews should catch that though, but given the budgets allocated to technical documentation these days, not too surprising they haven't.
What sucks is when there is no real feedback channel from customers that would allow fixing documentation when it's incorrect. Often there is very little of that, and still for the same reason, budget.

But yeah, it's hard to write 100% correct technical documentation without any strong process to check for correctness. At least when it comes to "bugs" that lead to a tangible defect (software or hardware bug), observing the issue is not hard (fixing it may), but when it comes to strictly abstract design (which a doc is), it's very hard to catch unless you have a strict process for that. Imagine writing software code that never gets compiled or tested, shiping it to customers and aiming for 100% correctness. Nobody would expect that. Just to give some perspective.

So let's just give design teams some budget for proper docs.

[T3sl4co1l]

What's funny is, the ancient datasheet (databook scans) that they replaced, probably contained all that, and more if you include the logic family introduction (which is basically what the application section is doing now).  Actually, they may well be rewriting (OCR, copy-paste, transcribe, whatever) that content, into the new format, and just not parsing it to find discrepancies like this.  Which, yeah, all comes down to department budget (and responsibility of management given that budget).

On the upside, NXP is a prominent competitor to TI in the logic space, and I haven't noticed gross defects in their documentation.  Sounds worthy of awarding some design wins eh?

Tim

[SiliconWizard]

Which is Nexperia actually, isn't it? Yeah, same boat. And yes, their datasheets are usually clean. And most of their parts have Schmitt trigger inputs, by the way.

[T3sl4co1l]

Ah yeah, it is Nexperia with logic. Think NXP datasheets still turn up quite often...

Tim