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

No, we're well down the curve. It was IBM's discontinuing OS/2 that started it. ;)

You used to be able to get 8.5 GHz PNPs (I have 100 or so of them).

Cheers

Phil Hobbs

The early days of analog IC design was all NPNs. There were some truly awful all-NPN opamps.

Back to the future, I suppose.

I spent most of my adulthood perfecting a pulse generator output stage circuit. When I finally got it almost right, the critical PNPs went EOL.

And as noted here, a billion-dollar product line has stopped because a

Which ones? Even the 709 had lateral PNPs.

The LM318 was probably the apogee. Of course it also had lateral PNPs in it, but to get it to go fast you had to bypass the level shifters by putting capacitors to the Vos adjust pins.

National had an app note where they tied both inputs to VEE and used a JFET matched pair with its collectors going to the Vos pins.

Both, depending on whether you're considering the folks that are going to get laid off or the ones whose heads are exploding (but will probably keep their jobs).

There are workarounds, such as real vs. folded cascodes and current source pullups with real or simulated inductors in series, but they all cost headroom, current, complexity, performance, or (usually) all four.

OTOH that all-NPN cascoded White follower circuit I posted last year works much better than the PNP wraparound, so all is not necessarily lost. ;)

Cheers

Phil Hobbs

Ah, OK, the uA702 was all-NPN, and it was pretty horrible.

The old TI datasheet for their version has a schematic:

The tail current generator is interesting.

Cheers

Phil Hobbs

GE made an opamp that used a zener internally as a level shifter. It made a nice noise generator.

ething.

I realize this is very stale.

Anyway, I had a call for a JFET recently. The J232 and perhaps 2N4116A look ed okay for what I needed. Only Interfet makes the J232 anymore, and I've n ever had experience with them.

OnSemi still has legacy stuff but has EOL'd some things. It seems that Cent ral Semi, Linear Systems, and Interfet live on legacy, and even welcome it. Central Semi and Linear Systems do bipolar parts, unlike Interfet. It made me think of this old thread. (I don't know the fabs they use.)

I haven't really done much with Central Semi & Linear Systems, so I don't k now what they are capable of. Did you consider a query to them on the BFT92 ?