https://www.allaboutcircuits.com/technical-articles/voltage-buffer-simulation-composite-amplifier-simulation-boost-output-current-drive/ -- 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"
2 GHz buffer with 2N390x
Started by ●February 23, 2020
Reply by ●February 23, 20202020-02-23
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 -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●February 23, 20202020-02-23
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 HobbsLooking 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. 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 ●February 23, 20202020-02-23
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.
Reply by ●February 23, 20202020-02-23
On Sun, 23 Feb 2020 16:34:51 -0800 (PST), Michael Terrell <terrell.michael.a@gmail.com> 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. -- 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 ●February 23, 20202020-02-23
On Monday, February 24, 2020 at 11:34:55 AM UTC+11, 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 from 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.Even I know that a 2N3055 is as slow as wet week.> He knew everything, yet he often needed help to repair a TV.And I certainly don't know everything, though I do know a lot more than Michael Terrell. The best definition of an expert is somebody who knows the limitations of their knowledge. -- Bill Sloman, Sydney
Reply by ●February 23, 20202020-02-23
"Michael Terrell" <terrell.michael.a@gmail.com> wrote in message news:1085d865-ec53-4158-aa2b-1446fff74951@googlegroups.com...> 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. >Entirely possible that he had done this, using a brand new epitaxial '3055. Which shouldn't even exist, it should've been discontinued and put in a new type number, say. While the one you had was made on the old process, and barely useful for audio. Although getting 5W even from an epitaxial version would probably require more skill than he had, anyway. I'm not doubting that possibility. Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Design Website: https://www.seventransistorlabs.com/
Reply by ●February 24, 20202020-02-24
On Sun, 23 Feb 2020 21:39:15 -0600, "Tim Williams" <tiwill@seventransistorlabs.com> wrote:>"Michael Terrell" <terrell.michael.a@gmail.com> wrote in message >news:1085d865-ec53-4158-aa2b-1446fff74951@googlegroups.com... >> 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.Getting that amount of power might have been possible in the past. The specifications for 2N3055 are quite relaxed. When some manufacturer tried to make some better transistors, but the die was out of specs for the intended transistor, but well inside 2N3055 specs, the manufacturer put the die in a TO-3 can and labeled it as "2N3055". This was fine, but some manufacturer labeled even failed VHF power transistors as "2N3055". When such transistor was put into a typical DC/audio circuit, the transistor might oscillate like hell somewhere in the VHF/UHF range :-)>Entirely possible that he had done this, using a brand new epitaxial '3055. >Which shouldn't even exist, it should've been discontinued and put in a new >type number, say. While the one you had was made on the old process, and >barely useful for audio. > >Although getting 5W even from an epitaxial version would probably require >more skill than he had, anyway. I'm not doubting that possibility. > >Tim
Reply by ●February 24, 20202020-02-24
On Sunday, February 23, 2020 at 10:39:15 PM UTC-5, Tim Williams wrote:> "Michael Terrell" wrote in message > news:1085d865-ec53-4158-aa2b-1446fff74951@googlegroups.com... > > 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. > > > > Entirely possible that he had done this, using a brand new epitaxial '3055. > Which shouldn't even exist, it should've been discontinued and put in a new > type number, say. While the one you had was made on the old process, and > barely useful for audio. > > Although getting 5W even from an epitaxial version would probably require > more skill than he had, anyway. I'm not doubting that possibility. > > TimIt was in a Pace 2300, a popular CB radio made by Pathcom in the '60s and '70s. He was convinced that the custom RF output in a TO-3 was just an ordinary audio transistor. I showed him the RCA Databook that showed it had no chance of working. He claimed that RCA didn't know what they were doing. The Databook was from 1967, and I may still have it somewhere. He had an attitude like Sloan. Anyone with a degree was infallible, and anyone else didn't deserve to live. I used to piss him off when I passed his bench at the shop. I would tell him what part was bad. He would curse me out, but more often than not he would yell, Do we have that part in stock. I took care of repairs of industrial electronics, and I knew our inventory better than anyone in the shop.
Reply by ●February 24, 20202020-02-24
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. :)
