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Re: Drives me Nuts

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On 2/02/2026 5:38 am, john larkin wrote:
> On Sun, 01 Feb 2026 17:31:41 +0000, Cursitor Doom <cd@notformail.com>
> wrote:
> 
>> Datasheets that don't provide pinouts. Even more annoying than Bill
>> Sloman.

But he didn't provide an example data sheet. One has to suspect that the 
pin-out data was there but in an unusual format.
> 
> There's lots of frustration in data sheets.
> 
> Block diagram and pinouts way down somewhere. It's not obvious what
> some parts actually do.
> 
> Silly block diagrams, if any.
> 
> Frequency response curves that hide bad things.

That's the free market for you.

> Table of contents at the end.
> 
> No DC data on RF parts. Adjust the gate bias trimpot until it works.

That's an unfortunate tradition. RF designers seem to be able to live it it.

> No outline drawing.
> 
> Crazy package names for standard packages.

That's the free market for you. It costs money to register a standard 
package.

> One data sheet for lots of different parts, with no way to tell which
> is which.

No way that John Larkin cna find.

> Application schematics that leave things out, or are flat wrong.

That's the free market for you. Engineers who can design things cost 
money, and the marketing department doesn't like paying for their time. 
Interns are a lot cheaper.

> "Murder Mystery" data sheets, where you have to read literally
> hundreds of pages and look here and there for clues.

It lets the marketing department hide the bad news. Texas Instruments 
used to leave out unattractive information when the had to pay for the 
paper it was printed on. Now they create very large .pdf documents to 
bury the bad news.

> Impossible keyword searches. There is a pin called MODE, but the word
> is used in many other places.
> 
> Pages of disclaimers and compliance junk.

The legal department likes to think that it is useful.

> Useless or insanely complex timing diagrams. Why can't they just say
> what the maximum SPI clock rate is?

Then they have to lay out the conditions necessary to let you get 
anywhere near that maximum rate - it tends to be situation dependent.

> The min/max input voltages are VCC+.3 and VEE-.3.  What happens beyond
> that?

Not their responsibility.

> No washability specs, or outright lies.

As if there was only one way of washing a printed circuit board.

> Recent issue: no transient overload specs on resistors.

Only on some resistors. Some resistor data sheets have quite a lot of 
information on transient overload limits. I've never seen one where they 
explained how the transient overload messed up the resistor, let alone 
what might be going on.

> No C:V data on ceramic caps. A 10uF 10v cap might be 2uF at 10 volts.

Some of them don't need it. The cheap and nasty ceramic capacitors where 
the capacitance is highly voltage dependent don't sell into particularly 
discriminating markets

> No negative voltage specs on aluminum caps. Some polymers are pretty
> good.

Anybody with any sense doesn't put any current into an electrolytic 
capacitor that might thin down the oxide layer that creates the 
capacitance. John Larkin should have paid more attention  to his 
chemistry lectures.

> No hints of over-voltage behavior on alum caps. Some just leak and get
> warm, some die hard with no warning.

They take the attitude that users shouldn't exceed the data sheet 
maximum voltage, so they don't have to spell how things can go wrong if 
they do.

> 1000 hour lifetime spec on alum caps. That's 40 days. Really?

The industry seems happy with it, for some parts. I seem to remember 
that some people sold high-reliablity parts with longer lives.

> Common-mode inductors with huge current ratings, but saturate with
> tiny normal-mode currents.

That's not a bug - that's a feature. That's why they are called 
common-mode inductors.

> Power inductor current specs that ignore skin and proximity effects.
> Envision smoke.

They should use the data sheet to warn unsophisticated users about that 
sort of problem, but most inductors are made for specific jobs, and they 
expect the users to know what they are doing.

> Impossible mosfet current and power ratings. IR started that nonsense.

Marketing seems to think that absolute maximum ratings which you could 
only obtain with liquid helium cooling are defensible.

> Important gotchas buried in tiny footnotes.

That marketing for you.

> .... just for starters...

Pollyanna optimists do read data sheets rather less carefully than they 
should.

-- 
Bill Sloman, Sydney

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Thread

Drives me Nuts Cursitor Doom <cd@notformail.com> - 2026-02-01 17:31 +0000
  Re: Drives me Nuts "Edward Rawde" <invalid@invalid.invalid> - 2026-02-01 13:26 -0500
  Re: Drives me Nuts john larkin <jl@glen--canyon.com> - 2026-02-01 10:38 -0800
    Re: Drives me Nuts Cursitor Doom <cd@notformail.com> - 2026-02-01 23:38 +0000
    Re: Drives me Nuts Bill Sloman <bill.sloman@ieee.org> - 2026-02-03 18:55 +1100
  Re: Drives me Nuts Bill Sloman <bill.sloman@ieee.org> - 2026-02-03 18:18 +1100

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