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Groups > sci.electronics.design > #460408
| From | Jan Panteltje <pNa0nStpealmtje@yahoo.com> |
|---|---|
| Newsgroups | sci.electronics.design |
| Subject | Re: Fast buffer idea |
| Date | 2017-05-15 19:13 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <ofculk$19cu$1@gioia.aioe.org> (permalink) |
| References | (7 earlier) <IMiSA.118013$ef.91898@fx34.iad> <XnsA7767E5052407idtokenpost@69.16.179.22> <ofcldu$n1m$1@gioia.aioe.org> <XnsA776875EB8A7idtokenpost@69.16.179.23> <MAlSA.118066$ef.9536@fx34.iad> |
On a sunny day (Mon, 15 May 2017 13:30:20 -0400) it happened bitrex <bitrex@de.lete.earthlink.net> wrote in <MAlSA.118066$ef.9536@fx34.iad>: >On 05/15/2017 01:18 PM, Steve Wilson wrote: >> Jan Panteltje <pNa0nStpealmtje@yahoo.com> wrote: >> >>> On a sunny day (Mon, 15 May 2017 16:24:56 GMT) it happened Steve >>> Wilson <no@spam.com> wrote in >>> <XnsA7767E5052407idtokenpost@69.16.179.22>: >>> >>>> bitrex <bitrex@de.lete.earthlink.net> wrote: >>>> >>>>> On 05/15/2017 10:09 AM, bitrex wrote: >>>>>> On 05/15/2017 10:01 AM, John Larkin wrote: >>>>>> >>>>>>> BW is 230 MHz as a unity-gain buffer. Each half of the dual will >>>>>>> source and sink 88 mA. And there are lots of faster THS-series >>>>>>> parts. >>>>>>> >>>>>>>> >>>>>>>> But indeed you can do that with a few NPNs of the old days, >>>>>>>> >>>>>>> >>>>>>> Post it. >>>>>> >>>>>> With discretes you can have: >>>>>> >>>>>> 1) wide bandwidth >>>>>> >>>>>> 2) low parts count >>>>>> >>>>>> 3) low quiescent current draw >>>>>> >>>>>> Pick two. >>>>> >>>>> The two transistor circuit Jan posted does have a pretty wide >>>>> bandwidth and a low parts count. It has a pretty nice small signal >>>>> output impedance, but its large-signal output impedance is bad. It >>>>> also draws a relatively large amount of quiescent current. >>>> >>>> I somehow missed the two transistor circuit that Jan posted. Can you >>>> please repost the link? >>>> >>>> Thanks >>> >>> From: >>> http://panteltje.com/panteltje/quadcopter/hud.html >>> the circuit diagram: >>> http://panteltje.com/panteltje/quadcopter/hud-0.1_circuit_diagram_IMG >>> _5984.JPG bottom left: >>> that has a gain of 2, so can drive a 75 Ohm cable with reasonable Zi. >>> The DC path requires an other 75 Ohm at the end of the cable. >> >> OK, thanks. >> >> That is a Sziklai Pair with a voltage divider in the feedback path: >> >> https://en.wikipedia.org/wiki/Sziklai_pair >> >> It would normally have the same thermal drift as a simple base-emitter >> junction, but the divide by two may increase it. >> >> The output impedance may be increased due to the low loop gain. The >> bandwidth is determined by the transistors you use. > >Its output impedance for large negative-going signals is _dogshit_, >regardless of what the small-signal analysis feedback-loop-gain etc. >calculations indicate. It can source current okay. It definitely can't >sink it. > >It doesn't really matter for a composite video signal, though, because >it's not really that wide a bandwidth signal. The only potentially >difficult fast full-level transition I think of would be if you have to >go from the "back porch" immediately to "full luminance." Well that is same as from black to white, works fine tough. that is just the PNP conducting pulling the output. This circuit has been used for video by me many many times. Never ever failed.
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Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 13:50 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 11:27 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-14 19:19 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 15:24 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 12:54 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:02 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 13:10 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:16 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:18 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 14:14 -0700
Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-15 19:51 +0100
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:17 -0700
Re: Fast buffer idea Clifford Heath <clifford.heath@gmail.com> - 2017-05-17 09:14 +1000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 16:26 -0700
Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-17 02:04 -0500
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-14 20:26 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:31 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:43 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 14:17 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-14 21:53 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 16:14 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 19:59 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:06 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 00:16 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:10 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 03:28 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:48 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 04:17 +0000
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 07:56 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 06:58 -0400
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 12:59 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-15 07:01 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 10:09 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 10:18 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-15 08:56 -0700
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 16:02 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 10:33 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 18:15 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 14:25 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 14:26 -0400
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 16:24 +0000
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 16:36 +0000
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 17:18 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:30 -0400
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 18:07 +0000
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:19 +0000
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 19:45 +0000
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 08:33 +0000
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:13 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:33 -0400
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 08:16 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-16 22:10 -0400
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:10 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-15 08:55 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 12:51 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 12:56 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:05 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 10:28 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:38 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 11:29 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 18:41 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:19 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 20:46 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:56 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 21:00 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 16:46 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 01:22 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 11:16 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 18:55 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 12:21 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 20:33 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 14:00 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 21:21 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 16:15 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 23:58 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 17:51 -0700
Re: Fast buffer idea pcdhobbs@gmail.com - 2017-05-16 16:30 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-17 00:16 +0000
Re: Fast buffer idea pcdhobbs@gmail.com - 2017-05-16 18:05 -0700
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 20:05 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-25 01:13 +0000
Re: Fast buffer idea Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-05-24 21:43 -0400
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-30 03:16 +0000
Re: Fast buffer idea Ralph Barone <ralph@invalid.com> - 2017-05-17 02:26 +0000
Re: Fast buffer idea Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-05-17 08:34 +0200
Re: Fast buffer idea Ralph Barone <ralph@invalid.com> - 2017-05-17 14:31 +0000
Re: Fast buffer idea Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-05-17 10:39 -0400
Re: Fast buffer idea Reinhardt Behm <rbehm@hushmail.com> - 2017-05-17 23:02 +0800
Re: Fast buffer idea Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-05-16 21:24 +0200
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 20:12 -0700
Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-25 04:38 -0700
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-25 07:28 -0700
Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-26 08:54 -0500
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-26 14:14 +0000
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-26 07:21 -0700
Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-16 20:27 +0100
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:05 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:19 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:21 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 20:56 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 17:37 -0400
Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-15 19:50 +0100
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:25 +0000
Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-16 20:19 +0100
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 14:33 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:15 -0400
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:05 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:38 -0400
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 08:12 +0000
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 18:47 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-16 21:52 -0400
Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-25 05:05 -0700
Re: Fast buffer idea pcdhobbs@gmail.com - 2017-05-25 05:42 -0700
Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-25 05:49 -0700
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-25 08:10 -0700
Re: Fast buffer idea Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-05-25 15:01 +0200
Re: Fast buffer idea "John Miles, KE5FX" <jmiles@gmail.com> - 2017-05-14 18:53 -0700
Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 02:45 +0000
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 15:23 -0400
Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-14 20:28 +0100
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:00 -0400
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:10 -0400
Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-14 17:58 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 23:13 -0400
Re: Fast buffer idea Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-16 17:27 -0700
Re: Fast buffer idea Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-16 17:34 -0700
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:14 -0700
Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-15 19:42 +0100
Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-16 03:29 -0500
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 06:57 -0700
Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-16 22:47 -0400
Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 20:18 -0700
Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-17 02:22 -0500
Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 14:05 +0000
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