General > General Technical Chat
Post the worst datasheet lies you've caught
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berke:
I propose 3 categories:

Category A - Flat lie - Device simply doesn't match the datasheet (example: goes poof at 5V even though supply range is said to be 3.3 to 6V)
Category B - Not a straight story - Datasheet is inconsistent, example it says 3.3V to 6V supply in the front page, but in footnote 3 of table 6. page 8 Vcc max is actually 5.3V
Category C - Lawyer talk - Datasheet makes you think something, but only upon very close examination it appears that that's not the case, or that some other parameter degrades so much that the device becomes useless.  Example: Sure our SPI port can run at 50 MHz!  (Yes well that's for output only, if you want to read MISO keep f < 27 MHz.)  Or sure the op-amp is rail-to-rail!  (But PSRR goes to trash.)
berke:
For this first example, I think it's category C.

The iMX8M reference manual says this:

Upon which I was expecting SPI operation at 52 MHz.  But yes you can transmit SPI data at 52 MHz, so it's technically correct.

A separate document, the datasheet says this:

Looks like if you want to read MISO you better stay below 23 MHz.
Psi:
Category B
I forget the datasheet, but it had text saying something like
"Pin X must be set low for correct operation"
and then it had a connection diagram that had pin X connected high.  |O

Also Category B i guess.
Another bad one is some of the ST LISxxxx accelerometers.
So much missing info or info from other accelerometers chips that doesn't apply to the one your reading.
Lots of head scratching involved and reading datasheets from other variants just so you can understand missing info from the chip you are using.
schmitt trigger:
There is also a category D: one in which important operating characteristics are left out. Chinese data sheets are masters in this respect.
tom66:
Category A, I guess.

I forget the exact device but I once designed an MCU into a product which had three SPI controllers advertised in the datasheet.

In the errata, there was this gem:
"Revision A1, A2.  Due to a silicon design error, SPI3 does not function.  Workaround: none."

So we ended up having to respin the board to connect to SPI2 instead.  Lesson learned...
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