I see that two of my favorite devices are now EOL.
BFU520A NXP 10 GHz NPN, 50 mA. About the best replacement for the BFT25A.
BFP640 and BFP650 SiGe NPN. Ridiculous Early voltage, 45 GHz , flat beta, super low noise.
I’ve ordered a reel or two of each, because I refuse to give up that much design space.
Foo.
Phil Hobbs
Yeah, fast discretes are going away. I guess all the mass-market stuff is using ICs now.
The c-b junction of the BFT25 was a nice diode, too. I measured 5 fA leakage.
And there seem to be no fast PNPs any more!
I sure hope the SAV parts stay around. I'm planning on using them in a pulse generator. That's a whole nother story.
John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
Yup. I use a lot of CPH3910, BFU520A, BFP640F or H, and a few others, in all sorts of things including TDRs and front ends. Looking to have JLCPCB hold some in stock for us to tide us over.
We've been investigating doing our own array parts, as a first step to doing our own ASICs. TinyTapeout lists a couple of BiCMOS processes with SiGe NPNs **and PNPs** with f_T between 130 and 350 GHz.
That's inconveniently high for what we do--we mostly care about high f_T at low collector current, good beta linearity, and very high Early voltage.
A start would be to make some 130 GHz SiGe NPN/PNP arrays with 0.5 pF or so connected from C to B (on chip) to slow them down a bit so that we can route them without making 30 GHz oscillators.
It'll need more work than just wiring up some BFP640s.
Cheers
Phil Hobbs
I'd really like to do a custom pulse generator output stage IC. A bunch of differential-output laser drivers, like SY88022 and the TI and Maxim equivalents, have all been EOLd at the same time. There must be something going on.
John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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