Favorite jellybean ~HF BJT?
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From: Joerg on 17 Dec 2009 19:08 John Larkin wrote: > On Thu, 17 Dec 2009 12:33:30 -0600, "Tim Williams" > <tmoranwms(a)charter.net> wrote: > >> 2N2369 is an old standby... kind of high current (200mA), like a '3904 sped >> up about 2-3 times. Not well specified though, I suppose because it's so >> old. I'm thinking in the 20V, 50mA range, fT maybe 0.5-1GHz. Like if you >> wanted to make old school RTL circuits that run as fast as 74S TTL. MPSH11 >> looks good, and '81 looks like its complement. I've used PN3563 before >> (complement PN4258? unobtainium?). >> >> Any favorites? >> >> I'm not looking for SMTs or anything over 3GHz. I'm still exploring the >> through-hole era, where it helps if the transistor doesn't oscillate on its >> own legs. :) >> >> Tim > > I like BFS17. It plenty fast but not so fast that it oscillates all on > its own, like many parts do. It is surface mount, which keeps the > parasitics down. > I always keep a (large) vial of those in stock here, just like we do with Sierra Nevada Pale Ale. Not sure why Tim absolutely wants thru-hole, SOT23 is easy to solder onto experimental board. Problem with thru-hole is that anything fast almost needs to be soldered down with its can like they did on old UHF tuner. And the market for that stuff is gone. > BFT25, Phil Hobbs' favorite transistor, is remarkable too. > That one is pretty low noise but at 20 cents incredibly expensive :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Bill Sloman on 17 Dec 2009 19:21 On Dec 17, 11:38 pm, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: > On a sunny day (Thu, 17 Dec 2009 14:58:51 -0600) it happened "Tim Williams" > <tmoran...(a)charter.net> wrote in <hge5uk$qh...(a)news.eternal-september.org>: > > BTW, here are the (LT) spice models for BFR91 and BFR96: > > .MODEL BFR91 NPN ( BF=101 VAF=96 VAR=9.6 RC=9 RB=5 > +RE=.149 IKF=0.25E-01 ISE=0.32E-14 TF=0.178E-10 > +TR=0.13E-08 ITF=0.40E-01 VTF=0.40E+01 CJC=1.271E-12 > +CJE=2.361E-12 XTI=3.0 NE=1.5 ISC=0.11E-14 EG=1.11 > +XTB=1.5 BR=2.63 VJC=0.75 VJE=0.75 IS=0.35E-15 > +MJC=0.33 MJE=0.33 XTF=4.0 IKR=0.25E-01 KF=0.1E-14 > +NC=1.7 FC=0.50 RBM=3.5 IRB=0.35E-02 XCJC=0.5 ) > > .MODEL BFR96 NPN ( BF=99 VAF=120 VAR=12.0 RC=6.1 RB=2.7 > +RE=.029 IKF=0.70E-01 ISE=0.90E-14 TF=0.178E-10 > +TR=0.13E-08 ITF=0.67E-01 VTF=0.50E+01 CJC=1.854E-12 > +CJE=1.709E-12 XTI=3.0 NE=1.5 ISC=0.30E-14 EG=1.11 > +XTB=1.5 BR=2.57 VJC=0.75 VJE=0.75 IS=0.10E-14 > +MJC=0.33 MJE=0.33 XTF=4.0 IKR=0.70E-01 KF=0.1E-14 > +NC=1.7 FC=0.50 RBM=1.9 IRB=0.10E-01 XCJC=0.5 ) > > I have appended these to standard.bjt I used a few BFR96 back in 1989-91, but we mostly used the BFR92 (NPN) and the BFT92 (PNP) where we needed some speed, always with around 33R (or thereabouts) of base-stopper, right up against the base. Cheap, easy to buy (Farnell) and tolerably quick.Won't take much reverse bias across the base. -- Bill Sloman, Nijmegen
From: Joel Koltner on 17 Dec 2009 20:15 "Joerg" <invalid(a)invalid.invalid> wrote in message news:7ovvgnFrfeU1(a)mid.individual.net... > That one is pretty low noise but at 20 cents incredibly expensive :-) You'll recall that Phil is from the optics world... :-)
From: John Larkin on 17 Dec 2009 21:50
On Thu, 17 Dec 2009 17:15:53 -0800, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"Joerg" <invalid(a)invalid.invalid> wrote in message >news:7ovvgnFrfeU1(a)mid.individual.net... >> That one is pretty low noise but at 20 cents incredibly expensive :-) > >You'll recall that Phil is from the optics world... :-) Yup. The c-b junction makes a low-capacitance fA-leakage diode. John |