Well, it happened--the last fast PNP is EOL

Since they're unique parts, perhaps we could persuade Lansdale or Rochester to make them--the litho resolution would be doable with very old equipment. Do you still have contacts there? I'd really like to be able to get the NE97733 again, too (8.5 GHz PNP).

Cheers

Phil Hobbs

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They sell for a lot more than digital transistors or BCX71s, and can't be much harder to make. Nexperia didn't take NXP's rf transistors or JFETs, so they're getting rid of them.

Cheers

Phil Hobbs

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Given the choice, TI is our preferred vendor, because they tend to keep stuff in production. Conversely, we avoid NXP.

I emailed ON and suggested they do some fast PNPs. They replied that demand is too small.

TI has some nice class-D amps.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Depends. Decades ago some engineers used the expression "Texan call-off" and I got involved in an urgent redesign because some kind of logamp had suddenly been discontinued.

I'll have to look at them again, ours was from Infineon. Problem is, we need 200V abs max for swing.

A company that made it onto my blacklist recently is Broadcom after they obsoleted a whole slew of discretes.

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Joerg

The EOL of discretes does keep fast circuit design interesting. GaN parts are cheap and fast, but don't come in P-channel!

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John Larkin         Highland Technology, Inc 
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John Larkin wrote: ..

I wondered that the military sector kept calm about the obsolation...

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Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de 

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Uwe Bonnes

Maybe we could get THAT or somebody to do them.

Cheers

Phil Hobbs

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Yeah, it's like doing chip design circa 1975--the NPNs are 100 times faster than the PNPs. :(

Cheers

Phil Hobbs

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There aren't that many... just 18 standard products between 1962 and

1970.... and they are listed on my home page, toward the bottom.

At 1970 I fled the corporate political world (I couldn't deal with all the political BS at Motorola... I think I quit 4-times just to force proper engineering decisions) and went to doing virtually all custom... with a few exceptions, like the LVDS chips for Fairchild.

(I supported my family at the time... 1970-1977, by running a hybrid line at Dickson Electronics and writing a lot of the course material for ICE... Integrated Circuit Engineering.)

At last count there were ~200 custom chips. I'll have to ponder and see if I can devise a non-disclosure way of listing those devices... and what they do functionally... if I can I'll post and announce.

In the last five years or so I've tired of chip design... there really isn't anything analog I haven't done before >:-}... so I've hopped into Behavioral Modeling... easy for me since I've done so much circuit work (and my math capabilities, at least up thru Calculus, are superb)... and it's fun, devising functional models which don't divulge any internal IP... a lot like puzzle solving in reverse ;-)

I will be updating the "Jim's Secret Sauce" page shortly, renaming it "Behavioral Modeling Gimmicks/Tools/Not sure yet"... with more explanations of how I got there. Watch for it. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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Most of my chip designs, transferred to Lansdale, are on the military preferred components list... they seem to love unconditionally stable OpAmps, even if the open-loop gain is only 75dB... though I'm sure the sliding-class-A outputs and 10V/us slew-rates grab their attention as well ;-) ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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"THAT" is a possibility ;-) I did a number of audio things for them, MANY moons ago... using those Intersil (?) wire-up-only chips. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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Any radhard opamps in there with CM input range to the negative rail and output to neg rail with pull-down? Will need that soon.

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Joerg
[snip]
[snip]

That's stretching history just a tweak... PNP's back then were _laterals_ ... 1MHz GBW product, if you were lucky. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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Not from my just-out-of-school era.

Today, I can easily design that for you... processing by X-Fab. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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I'll find some off-the-shelf from "the usual suspects", was just wondering if there was a genuine Thompson amp around in rad-hard.

Sometimes the just out of school designs are like VW Beetles. I have one that runs off the conveyor belt since the 90's, now in Shenzhen, no end in sight.

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Joerg

We did use lots of OP484 :-)

Cheers, Gerhard

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Gerhard Hoffmann

The PNP CK722 was the fastest transistor when I was a kid.

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John Larkin         Highland Technology, Inc 
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NXP: Not recommended for new designs.

Gerhard

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Gerhard Hoffmann

Am 05.06.2018 um 21:05 schrieb Phil Hobbs:

Or Diodes, Inc.

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Gerhard Hoffmann

Though I am sure the taxpayer was ultimately on the hook for those :-)

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