Declining datasheet quality

Discussion:

(too old to reply)

Don Y

2024-05-01 00:53:18 UTC

A colleague teaching a STEM course asked me for some details on WS2812's.
Digging through the datasheets I've been able to find seems like they
are sold only to hobbyists -- or, at least not to folks who have to
*design* with them!

I can't seem to find any specification of Icc -- at MAX (255.255.255)
intensity and "dark" (0.0.0).

Nor anything giving thermal characteristics of the package beyond
ambient (70C) and max junction temperature (80C) -- I suspect it
wouldn't be hard to melt the things if they dissipate any
appreciable amount of power!

Is this the "typ" trend taken to its logical extreme (where we
don't really care how it MIGHT work in a given environment, beyond
"try it and see"?)

John Larkin

2024-05-01 01:20:53 UTC

Permalink

On Tue, 30 Apr 2024 17:53:18 -0700, Don Y

Post by Don Y
A colleague teaching a STEM course asked me for some details on WS2812's.
Digging through the datasheets I've been able to find seems like they
are sold only to hobbyists -- or, at least not to folks who have to
*design* with them!
I can't seem to find any specification of Icc -- at MAX (255.255.255)
intensity and "dark" (0.0.0).
Nor anything giving thermal characteristics of the package beyond
ambient (70C) and max junction temperature (80C) -- I suspect it
wouldn't be hard to melt the things if they dissipate any
appreciable amount of power!
Is this the "typ" trend taken to its logical extreme (where we
don't really care how it MIGHT work in a given environment, beyond
"try it and see"?)

Data sheets are increasingly awful. Some don't even say what the part
does. Some mechanical drawings have missing dims. And where is pin 1?

People randomly distribute abs max, pin function tables, equivalent
schematics, electrical characteristics, whatever. Often there is no
date or version number. File names are bizarre, unrelated to the part
number.

I especially hate a data sheet that covers a bunch of parts and
doesn't tell you what the difference is between them.

Or covers a zillion parts and makes me build the part number, and then
guess whether it's an available thing.

This isn't really bad:

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://cdn-shop.adafruit.com/datasheets/WS2812.pdf&ved=2ahUKEwi9sYqdpOuFAxV6IDQIHX-dCJ0QFnoECB0QAQ&usg=AOvVaw2wZFi_i6GR7eWbT12yqVZd

john larkin

2024-05-02 18:59:38 UTC

Permalink

On Tue, 30 Apr 2024 18:20:53 -0700, John Larkin

Post by John Larkin
On Tue, 30 Apr 2024 17:53:18 -0700, Don Y

Data sheets are increasingly awful. Some don't even say what the part
does. Some mechanical drawings have missing dims. And where is pin 1?
People randomly distribute abs max, pin function tables, equivalent
schematics, electrical characteristics, whatever. Often there is no
date or version number. File names are bizarre, unrelated to the part
number.
I especially hate a data sheet that covers a bunch of parts and
doesn't tell you what the difference is between them.
Or covers a zillion parts and makes me build the part number, and then
guess whether it's an available thing.
https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://cdn-shop.adafruit.com/datasheets/WS2812.pdf&ved=2ahUKEwi9sYqdpOuFAxV6IDQIHX-dCJ0QFnoECB0QAQ&usg=AOvVaw2wZFi_i6GR7eWbT12yqVZd

Here's a good (ie, bad) data sheet example.

https://www.rohm.com/datasheet?p=SH8JC5&dist=Digi-key&media=referral&source=digi-key.com&campaign=Digi-key

It's not clear when they are talking about one die or two. The word
"and" is not helpful.

It's not clear if this is one or two die, which can matter. I'll x-ray
one.

Phil Hobbs

2024-05-02 22:18:24 UTC

Permalink

Post by john larkin
On Tue, 30 Apr 2024 18:20:53 -0700, John Larkin

Post by John Larkin
On Tue, 30 Apr 2024 17:53:18 -0700, Don Y

Data sheets are increasingly awful. Some don't even say what the part
does. Some mechanical drawings have missing dims. And where is pin 1?
People randomly distribute abs max, pin function tables, equivalent
schematics, electrical characteristics, whatever. Often there is no
date or version number. File names are bizarre, unrelated to the part
number.
I especially hate a data sheet that covers a bunch of parts and
doesn't tell you what the difference is between them.
Or covers a zillion parts and makes me build the part number, and then
guess whether it's an available thing.
https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://cdn-shop.adafruit.com/datasheets/WS2812.pdf&ved=2ahUKEwi9sYqdpOuFAxV6IDQIHX-dCJ0QFnoECB0QAQ&usg=AOvVaw2wZFi_i6GR7eWbT12yqVZd

Here's a good (ie, bad) data sheet example.
https://www.rohm.com/datasheet?p=SH8JC5&dist=Digi-key&media=referral&source=digi-key.com&campaign=Digi-key
It's not clear when they are talking about one die or two. The word
"and" is not helpful.
It's not clear if this is one or two die, which can matter. I'll x-ray
one.

Good idea.

I’d be very surprised if it were monolithic—you’d need extra die thickness
for the isolation, and there’s no benefit versus just using two dice. Plus
of course it would be a lower volume special purpose part.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

john larkin

2024-05-02 23:38:01 UTC

Permalink

On Thu, 2 May 2024 22:18:24 -0000 (UTC), Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Tue, 30 Apr 2024 18:20:53 -0700, John Larkin

Post by John Larkin
On Tue, 30 Apr 2024 17:53:18 -0700, Don Y

Data sheets are increasingly awful. Some don't even say what the part
does. Some mechanical drawings have missing dims. And where is pin 1?
People randomly distribute abs max, pin function tables, equivalent
schematics, electrical characteristics, whatever. Often there is no
date or version number. File names are bizarre, unrelated to the part
number.
I especially hate a data sheet that covers a bunch of parts and
doesn't tell you what the difference is between them.
Or covers a zillion parts and makes me build the part number, and then
guess whether it's an available thing.
https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://cdn-shop.adafruit.com/datasheets/WS2812.pdf&ved=2ahUKEwi9sYqdpOuFAxV6IDQIHX-dCJ0QFnoECB0QAQ&usg=AOvVaw2wZFi_i6GR7eWbT12yqVZd

Here's a good (ie, bad) data sheet example.
https://www.rohm.com/datasheet?p=SH8JC5&dist=Digi-key&media=referral&source=digi-key.com&campaign=Digi-key
It's not clear when they are talking about one die or two. The word
"and" is not helpful.
It's not clear if this is one or two die, which can matter. I'll x-ray
one.

Good idea.
Id be very surprised if it were monolithicyoud need extra die thickness
for the isolation, and theres no benefit versus just using two dice. Plus
of course it would be a lower volume special purpose part.
Cheers
Phil Hobbs

Dual transistors usually aren't.

john larkin

2024-05-02 22:56:02 UTC

Permalink

Post by john larkin
On Tue, 30 Apr 2024 18:20:53 -0700, John Larkin

Post by John Larkin
On Tue, 30 Apr 2024 17:53:18 -0700, Don Y

Data sheets are increasingly awful. Some don't even say what the part
does. Some mechanical drawings have missing dims. And where is pin 1?
People randomly distribute abs max, pin function tables, equivalent
schematics, electrical characteristics, whatever. Often there is no
date or version number. File names are bizarre, unrelated to the part
number.
I especially hate a data sheet that covers a bunch of parts and
doesn't tell you what the difference is between them.
Or covers a zillion parts and makes me build the part number, and then
guess whether it's an available thing.
https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://cdn-shop.adafruit.com/datasheets/WS2812.pdf&ved=2ahUKEwi9sYqdpOuFAxV6IDQIHX-dCJ0QFnoECB0QAQ&usg=AOvVaw2wZFi_i6GR7eWbT12yqVZd

Here's a good (ie, bad) data sheet example.
https://www.rohm.com/datasheet?p=SH8JC5&dist=Digi-key&media=referral&source=digi-key.com&campaign=Digi-key
It's not clear when they are talking about one die or two. The word
"and" is not helpful.
It's not clear if this is one or two die, which can matter. I'll x-ray
one.

Loading Image...