Favorite jellybean ~HF BJT?

John Larkin wrote:
> On Thu, 17 Dec 2009 12:33:30 -0600, "Tim Williams"
> <tmoranwms@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.

On Dec 17, 11:38=A0pm, Jan Panteltje <pNaonStpealm...@yahoo.com> wrote:
> On a sunny day (Thu, 17 Dec 2009 14:58:51 -0600) it happened "Tim William=
s"
> <tmoran...@charter.net> wrote in <hge5uk$qh...@news.eternal-september.org=
>:
>
> BTW, here are the (LT) spice models for BFR91 and BFR96:
>
> .MODEL BFR91 NPN ( BF=3D101 =A0VAF=3D96 =A0VAR=3D9.6 =A0RC=3D9 RB=3D5
> +RE=3D.149 =A0IKF=3D0.25E-01 =A0ISE=3D0.32E-14 =A0TF=3D0.178E-10
> +TR=3D0.13E-08 =A0ITF=3D0.40E-01 =A0VTF=3D0.40E+01 =A0CJC=3D1.271E-12
> +CJE=3D2.361E-12 =A0XTI=3D3.0 =A0NE=3D1.5 =A0ISC=3D0.11E-14 =A0EG=3D1.11
> +XTB=3D1.5 =A0BR=3D2.63 =A0VJC=3D0.75 =A0VJE=3D0.75 =A0IS=3D0.35E-15
> +MJC=3D0.33 =A0MJE=3D0.33 =A0XTF=3D4.0 =A0IKR=3D0.25E-01 =A0KF=3D0.1E-14
> +NC=3D1.7 =A0FC=3D0.50 =A0RBM=3D3.5 =A0IRB=3D0.35E-02 =A0XCJC=3D0.5 )
>
> .MODEL BFR96 NPN ( BF=3D99 =A0VAF=3D120 =A0VAR=3D12.0 =A0RC=3D6.1 RB=3D2.=
7
> +RE=3D.029 =A0IKF=3D0.70E-01 =A0ISE=3D0.90E-14 =A0TF=3D0.178E-10
> +TR=3D0.13E-08 =A0ITF=3D0.67E-01 =A0VTF=3D0.50E+01 =A0CJC=3D1.854E-12
> +CJE=3D1.709E-12 =A0XTI=3D3.0 =A0NE=3D1.5 =A0ISC=3D0.30E-14 =A0EG=3D1.11
> +XTB=3D1.5 =A0BR=3D2.57 =A0VJC=3D0.75 =A0VJE=3D0.75 =A0IS=3D0.10E-14
> +MJC=3D0.33 =A0MJE=3D0.33 =A0XTF=3D4.0 =A0IKR=3D0.70E-01 =A0KF=3D0.1E-14
> +NC=3D1.7 =A0FC=3D0.50 =A0RBM=3D1.9 =A0IRB=3D0.10E-01 =A0XCJC=3D0.5 )
>
> 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

"Joerg" <invalid@invalid.invalid> wrote in message 
news:7ovvgnFrfeU1@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... :-)

On Thu, 17 Dec 2009 17:15:53 -0800, "Joel Koltner"
<zapwireDASHgroups@yahoo.com> wrote:

>"Joerg" <invalid@invalid.invalid> wrote in message 
>news:7ovvgnFrfeU1@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