Re: Datasheet-flation?

On Thu, 28 Nov 2024 18:22:03 -0500, ehsjr <ehsjr@verizon.net> wrote:

On 11/26/2024 10:21 PM, Dave Platt wrote:

Back on the original subject a bit: it's not just huge data sheets
which can be... well, less than wonderful.  I invite you to take a
look at the sheet for the Skyworks SKY65050-372LF low noise
transistor.  The evaluation board schematic on page 8, and its
associated bill of materials, invite careful examination.
 
The fact that they went to the trouble of actually _saying_ that
the schematic diagram is a mess, rather than actually fixing it...
well, I assume this was a Management decision.  I think I'd
have been ashamed to be the Engineer, though.
 

>
It seems that the block diagram on page 1 may establish
the caliber of the documentation. :-(
>
(What's the emoticon for hold your nose?)
Ed

It's not even a block.

The RF geeks like to call fet pins RF_IN and RF_OUT and RF_COM,
whereas normal people say gate, drain, source. Maybe compromise on
SOME and MORE and NONE.

And their biasing algorithm is usually "turn the pot until it works."

I use $100 RF switches and PHEMTs and MMICs and $300 distributed amp
chips in time domain, to make pulses. The data sheets are pretty much
useless to me. You never know if a part will actually work under 100
MHz (some won't) , or if that's as low as their VNA will go.

Mini-Circuits has assured me that they have no interest in amplifying
pulses and will never have Spice models for their parts.

I wonder if Q-spice is intended to bring RF design into the 20th
Century. It's the 21st already so it's overdue.

We had to add a DC block here, and it didn't help that some of the RF
parts were poorly specified.

https://www.dropbox.com/scl/fi/3j1eyfu850n5bb3xwlx10/DC_Block.jpg?rlkey=055ej3zuo5siukis8q0aaj8ft&raw=1