why do they do this?

Take a look at this two page "Cheat Sheet" aide memoire from TI:

formatting link

ISO 9xxx whatever plus forcing the customer to interact with marketing early, makes sense to me. SLVA450 ? SNVA364 ?

Yet many, many years later I can still remember to search for "The Taming of the Slew" from Jim Williams. Or "XYZs of Oscilloscopes" from Tek.

Don't get me started on AD's recent email asking me to search the support forum on an AD633 question. Barrie Gilbert passed on, so I guess they had no one to ask... Steve

Reply to
sroberts6328
Loading thread data ...

Is it stable with low ESR caps? We use polymers or ceramics mostly.

We need so many goofy voltages that we usually buy adjustable regulators for stock. The board that I'm doing now has a 24-channel analog mux to BIST the power supplies, using the dreadful Xilinx

1-volt XADC that's inside their FPGAs. Free and worth it.

Well, some never show any sign of manners. They are repulsive but you've got to feel sorry for them, stuck being around themselves all day.

There's a basically perfect -1 correlation between being obnoxious and designing electronics.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

Well, now that Jim Thompson is apparently no longer with us. :(

He was a bit of a statistical outlier.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
 Click to see the full signature
Reply to
Phil Hobbs

opa1622_revA.pdf would be even better. We have a nice file name convention for docs and PCBs and software, including working edits and formal revs.

Just when they were doing so well, they assign silly random number file names to app notes and eval board docs.

I love data sheets like LM9999final.pdf

They can never change that!

Analog Devices is famous for issuing preliminary data sheets, full of mistakes, and leaving them that way for years.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

Easy. LM9999_revA.pdf.

I rename the meaningless data sheets.

We had a series of very intense/interesting meetings about this. We settled on a telephone-number format, 123-4567 for all parts. We have a document SACRED.TXT that explains all the rules.

I know of one big company that assigns a 12-digit number to anything. Parts. Products. Drawings. Trucks. Buildings. Employees.

I've worked for companies that just assigned the next sequential number to anything. If you know the PCB number, you had to look in the log book to find the schematic. The numbers were totally unrelated.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

I have a few of the old databooks that are great. The old TI TTL book, a couple of National and Motorola books, and some discrete data books, with *graphs*.

IC data sheets used to include internal schematics. Now you have to test or guess or ask on a forum, so someone else can guess for you.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

We have a PDATA folder for every part in our inventory system. It gets data sheets, readme files, photos, links, test results, anything we want to remember. Files like DONT_USE.TXT or BAD_BAD.doc

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

AMP/Tyco was famous for messing with your head.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

TI used to divert you to some goofy server to get a data sheet. Now you just click!

If you are big enough to deserve the attention of a product support person, they will post your question to a forum for you.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

I've used them with 1-10uF MLCCs at input and output. No problem so far.

formatting link
You may also want to look at their full range of LDOs here
formatting link

Reply to
Pimpom

More than just schematics; the mustard TTL databook had schematics that actually were also layout topologies; no wires ever crossed unless they went in/out of a transistor base (the base diffusion was a cross-under conductor or a resistor, depending on which you needed).

Reply to
whit3rd

fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V.

RR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR . And the thermal impedance specs are so bad, you just try getting 800mA ou t of it with any kind voltage headroom without using a liquid nitrogen drip .

eventually going to have a good chance at killing him, and that he's in th e age group where it's quite likely to succeed.

's what's going to happen is gradually creeping up on him, and he doesn't l ike it at all.

Okay- so you can now add psychology to all your other disqualifications.

Reply to
bloggs.fredbloggs.fred

fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V.

SRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSR R. And the thermal impedance specs are so bad, you just try getting 800mA o ut of it with any kind voltage headroom without using a liquid nitrogen dri p.

Seriously! Rigging up your little pseudo-LDO is not "designing" electronics . That's like saying figuring the part number suffix for the fixed 1.5V out put is "designing" electronics.

Reply to
bloggs.fredbloggs.fred

r fake dropout specs while conveniently omitting the fact that Vbias must b e greater than Vout + 1.5V.

PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PS RR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen dr ip.

is eventually going to have a good chance at killing him, and that he's in the age group where it's quite likely to succeed.

at's what's going to happen is gradually creeping up on him, and he doesn't like it at all.

That was comedy, not psychology. Fred didn't get the joke.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V.

SRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSR R. And the thermal impedance specs are so bad, you just try getting 800mA o ut of it with any kind voltage headroom without using a liquid nitrogen dri p.

And John Larkin likes to think that he "designs" his electronics so he's ju st flattering himself.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

Rolling your own opamp-nfet LDO is not designing electronics?

The loop could oscillate; transient load-step response matters; the fet could oscillate; the fet could fry; the loop dynamics changes radically at low dropout voltages, when the fet becomes ohmic; loads could have different C and ESR and stuff. This takes design.

You seem to think that all electronic design is trivial. Well, whatever it is, I enjoy it. You should find something to enjoy.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

eir fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V.

ts

B PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800m A out of it with any kind voltage headroom without using a liquid nitrogen drip.

ics. That's like saying figuring the part number suffix for the fixed 1.5V output is "designing" electronics.

Of course it is, but you're not doing that.

It would be foolish getting distracted by that minutia when you have a much bigger task to complete. Take the non-design off the shelf LDO approach.

If the engineering is non-trivial, it will probably end up being problemati c. The best products are trivialized engineering.

Reply to
bloggs.fredbloggs.fred

eir fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V.

ts

B PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800m A out of it with any kind voltage headroom without using a liquid nitrogen drip.

ics. That's like saying figuring the part number suffix for the fixed 1.5V output is "designing" electronics.

Yes, a feedback circuit can be unstable. You have told us your method of f inding and fixing such issues is iteration through simulation and then on t he test bench rather than applying math which will give you the right answe r the first time.

So does applying iteration make you a designer or a tinkerer? Iteration is the method most amateurs use.

I'm presently working on a board for a ventilator. The engineering isn't s o hard other than trying to get the simulation models working. LTspice can be a real chore when a model isn't available off the shelf. There is so l ittle documentation available on the digital parts that the only way to ass ure the behavior is to test the model thoroughly before using it in your ci rcuit.

I found that the DFLOP model has undocumented and unexpected behavior when both SET and CLEAR inputs are asserted simultaneously. No one in the LTspi ce group knew about this. Rather than even address it seriously they indic ated I should not expect any particular behavior, the parts work as the des igner intended. I wasn't complaining about the behavior as much as I was c omplaining that it was not just unexpected, but undocumented.

Many times LTspice is a sucky tool to use especially if you need to use the Help.

--
  Rick C. 

  -+ Get 1,000 miles of free Supercharging 
 Click to see the full signature
Reply to
Ricketty C

Do I have to give the money back?

But electronic design is minutia, especially when you want your boards to work first try.

Show us some.

--
John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
 Click to see the full signature
Reply to
John Larkin

What about an LM-5050? It either works, or it doesn't. :)

Reply to
mpm

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.