The article is not about the 2GHz buffer. A 200MHz buffer will work here too, that's why they don't care about it.
Reply by ●February 25, 20202020-02-25
On Monday, 24 February 2020 00:34:55 UTC, Michael Terrell wrote:
> That reminds of of a guy with a brand new two year degree who believe that he could get 5W of RF at 27 MHz form a 2N3055. I gave him one. As I expected, he didn't even get a miliwatt output, which was as low as I could measure in my home shop at 17. He was like Sloman. He knew everything, yet he often needed help to repair a TV.
To be fair you can get 5w of 27MHZ out of a 3055... just feed 5w at 27MHz into all 3 terminals.
3055s were greased lightning compared to germanium power trans.
NT
Reply by Mikko OH2HVJ●February 25, 20202020-02-25
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> writes:
> On 2020-02-24 16:36, Mikko OH2HVJ wrote:
>> I've measured 30-300 MHz depending on mfg 1994-2015. Processes evolve and
>> generic partnumbers, too.
>>
>
> 30 MHz peak f_T for a 2N3904?
>
> 350-400 MHz at ~10-30 mA iirc.
Dang! - My measurments were not full characterization, but in-circuit
with low I_c. So, not peak and I_c might explain most of the variation!
Now that I've got the gear, I could do proper measurements if I can find
some older ones.
Thanks for spotting that out!
--
mikko
Reply by Joerg●February 24, 20202020-02-24
On 2020-02-23 12:56, jlarkin@highlandsniptechnology.com wrote:
That reminds me of the moped tuning that the guys did in my high school
days. Going 50mph on a screaming 50ccm engine running way beyond
redline. Unfortunately one classmate died that way, the brakes couldn't
hold up.
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by Phil Hobbs●February 24, 20202020-02-24
On 2020-02-24 16:36, Mikko OH2HVJ wrote:
> George Herold <ggherold@gmail.com> writes:
>
>> Huh OK his gain graph droops at ~100MHz...
>> So what is the Ft (typical) of a 2n3904?
>
> I've measured 30-300 MHz depending on mfg 1994-2015. Processes evolve and
> generic partnumbers, too.
>
30 MHz peak f_T for a 2N3904?
350-400 MHz at ~10-30 mA iirc.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com
Reply by George Herold●February 24, 20202020-02-24
On Monday, February 24, 2020 at 4:36:47 PM UTC-5, Mikko OH2HVJ wrote:
> George Herold <ggherold@gmail.com> writes:
>
> > Huh OK his gain graph droops at ~100MHz...
> > So what is the Ft (typical) of a 2n3904?
>
> I've measured 30-300 MHz depending on mfg 1994-2015. Processes evolve and
> generic partnumbers, too.
>
> --
> mikko
Thanks!
GH
Reply by Mikko OH2HVJ●February 24, 20202020-02-24
George Herold <ggherold@gmail.com> writes:
> Huh OK his gain graph droops at ~100MHz...
> So what is the Ft (typical) of a 2n3904?
I've measured 30-300 MHz depending on mfg 1994-2015. Processes evolve and
generic partnumbers, too.
--
mikko
Reply by ●February 24, 20202020-02-24
On Mon, 24 Feb 2020 09:15:38 -0800 (PST), George Herold
<ggherold@gmail.com> wrote:
>On Sunday, February 23, 2020 at 5:02:33 PM UTC-5, jla...@highlandsniptechnology.com wrote:
>> On Sun, 23 Feb 2020 16:42:42 -0500, Phil Hobbs
>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>
>> >On 2020-02-23 15:56, jlarkin@highlandsniptechnology.com wrote:
>> >>
>> >> https://www.allaboutcircuits.com/technical-articles/voltage-buffer-simulation-composite-amplifier-simulation-boost-output-current-drive/
>> >>
>> >>
>> >>
>> >Gee, I wish I were smart enough to design that.
>> >
>> >I once tried fairly hard to bandage up a MAT14 supermatch quad NPN to
>> >make it work at higher bandwidth, by using gussied-up Darlington
>> >connections with 40-GHz SiGe:C NPNs to return the AC base current to the
>> >collector circuit.
>> >
>> >It didn't work, because AFAICT there's no simple way to get rid of the
>> >time constants formed by Rbb' and the interelectrode capacitances
>> >without trashing the noise.
>> >
>> >Cheers
>> >
>> >Phil Hobbs
>>
>> Looking at his graphs, I figure that after the Ft's run out, the
>> signal is coupled through the various Cbe's. But that's not much in
>> the way of gain. Thermal runaway could be interesting too.
>
>Huh OK his gain graph droops at ~100MHz...
>So what is the Ft (typical) of a 2n3904?
250 MHz sort of range. The PNP is a bit less than the NPN.
--
John Larkin Highland Technology, Inc
The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
Reply by George Herold●February 24, 20202020-02-24
On Sunday, February 23, 2020 at 5:02:33 PM UTC-5, jla...@highlandsniptechnology.com wrote:
> On Sun, 23 Feb 2020 16:42:42 -0500, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
> >On 2020-02-23 15:56, jlarkin@highlandsniptechnology.com wrote:
> >>
> >> https://www.allaboutcircuits.com/technical-articles/voltage-buffer-simulation-composite-amplifier-simulation-boost-output-current-drive/
> >>
> >>
> >>
> >Gee, I wish I were smart enough to design that.
> >
> >I once tried fairly hard to bandage up a MAT14 supermatch quad NPN to
> >make it work at higher bandwidth, by using gussied-up Darlington
> >connections with 40-GHz SiGe:C NPNs to return the AC base current to the
> >collector circuit.
> >
> >It didn't work, because AFAICT there's no simple way to get rid of the
> >time constants formed by Rbb' and the interelectrode capacitances
> >without trashing the noise.
> >
> >Cheers
> >
> >Phil Hobbs
>
> Looking at his graphs, I figure that after the Ft's run out, the
> signal is coupled through the various Cbe's. But that's not much in
> the way of gain. Thermal runaway could be interesting too.
Huh OK his gain graph droops at ~100MHz...
So what is the Ft (typical) of a 2n3904?
George H.
>
> The electronic mags are pitiful these days.
>
> Speaking of buffers, BUF602 is slick.
>
>
>
> --
>
> John Larkin Highland Technology, Inc
>
> The cork popped merrily, and Lord Peter rose to his feet.
> "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
Reply by George Herold●February 24, 20202020-02-24
On Monday, February 24, 2020 at 1:23:38 AM UTC-5, jla...@highlandsniptechnology.com wrote:
> On Sun, 23 Feb 2020 22:07:55 -0800 (PST), Michael Terrell
> <terrell.michael.a@gmail.com> wrote:
>
> >On Sunday, February 23, 2020 at 8:26:09 PM UTC-5, highlandsniptechnology wrote:
> >> On Sun, 23 Feb 2020 16:34:51 -0800 (PST), Michael Terrell wrote:
> >>
> >> >On Sunday, February 23, 2020 at 4:42:53 PM UTC-5, Phil Hobbs wrote:
> >> >> On 2020-02-23 15:56, jlarkin wrote:
> >> >> >
> >> >> > https://www.allaboutcircuits.com/technical-articles/voltage-buffer-simulation-composite-amplifier-simulation-boost-output-current-drive/
> >> >> >
> >> >> >
> >> >> >
> >> >> Gee, I wish I were smart enough to design that.
> >> >>
> >> >> I once tried fairly hard to bandage up a MAT14 supermatch quad NPN to
> >> >> make it work at higher bandwidth, by using gussied-up Darlington
> >> >> connections with 40-GHz SiGe:C NPNs to return the AC base current to the
> >> >> collector circuit.
> >> >>
> >> >> It didn't work, because AFFLICT there's no simple way to get rid of the
> >> >> time constants formed by Rbb' and the interelectrode capacitances
> >> >> without trashing the noise.
> >> >
> >> >
> >> > That reminds of of a guy with a brand new two year degree who believe that he could get 5W of RF at 27 MHz form a 2N3055. I gave him one. As I expected, he didn't even get a miliwatt output, which was as low as I could measure in my home shop at 17. He was like Sloman. He knew everything, yet he often needed help to repair a TV.
> >>
> >> The guy is no lightweght. Maybe he was in a hurry or something.
> >
> >Which guy? There are too many guys in this thread. :)
>
> Dr. Sergio Franco.
Huh S. Franco wrote one of my favorite opamp books. I better go read the
article. (I thought it was hooey from the comments.)
George H.
>
>
>
>
> --
>
> John Larkin Highland Technology, Inc
>
> The cork popped merrily, and Lord Peter rose to his feet.
> "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"