Groups > sci.electronics.design > #447208

Re: An old "500MC biquinary counter"

From	Joerg <news@analogconsultants.com>
Newsgroups	sci.electronics.design
Subject	Re: An old "500MC biquinary counter"
Date	2017-02-10 13:26 -0800
Message-ID	<eg6peeFli2gU1@mid.individual.net> (permalink)
References	<M0mnA.448$SQ3.75@fx29.iad> <eg6ag4Fig75U1@mid.individual.net> <o7l7tq$fq1$1@dont-email.me>

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On 2017-02-10 12:32, Piglet wrote:
> On 10/02/2017 17:10, Joerg wrote:
>> On 2017-02-10 08:39, bitrex wrote:
>>> What are D1-D5?
>>>
>>> http://www.seekic.com/uploadfile/ic-circuit/s2009713233931554.gif
>>
>>
>> Could they be Shockley diodes? Those are similar to SCRs but without a
>> gate connection and can only be triggered via avalanche breakdown or
>> dv/dt.
>>
>
> Yeah could be Shockley diodes (aka 4-layer diodes) but last time I saw
> one in a schematic the symbol was different. However they are not
> hi-speed parts and even in their heyday would not have seen use at 00s
> of kilohertz let alone megahertz.
>

Schematic symbols in the olden days were often weird. Take a look at the 
potmeter representations here (9th and 10th left from the top):

http://www.radiomuseum.org/forumdata/users/133/Symbols_2_590.png


> Diac is a still-available kindof breakover diode but higher voltage and
> bidirectional. 4-layer diodes I saw were made with breakover voltages
> from 8 to 22V and 5-10% tolerance. TC was remarkable good and they made
> good semi-precise timers (but not for nano-seconds). Diacs typically
> breakover 28-35V and are not tightly specified.
>
> Another option is that is just an old symbol for a zener diode?
>
> But for those speeds I reckon they must be tunnel diodes. That would tie
> in with the emitter coupled logic and 10mA tail current. Tunnel diodes
> are fast. Due to the very high doping some older ones have now diffused
> themselves into mush.
>

That IC could be from an era where a few hundred kHz was considered 
blazingly fast. Shockley diodes would offer the nice advantage of 
introducing hysteresis which improves the noise robustness of this counter.

With tunnel diodes I wouldn't know who they'd integrate those onto a chip.

-- 
Regards, Joerg

http://www.analogconsultants.com/

Thread

An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-10 11:39 -0500
  Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 09:10 -0800
    Re: An old "500MC biquinary counter" "tom" <tmiller11147@verizon.net> - 2017-02-10 13:24 -0500
      Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 11:30 -0800
        Re: An old "500MC biquinary counter" pcdhobbs@gmail.com - 2017-02-10 12:36 -0800
          Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 14:15 -0800
            Re: An old "500MC biquinary counter" Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-10 13:16 -0500
              Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 16:14 -0800
                Re: An old "500MC biquinary counter" Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-10 19:19 -0500
    Re: An old "500MC biquinary counter" pcdhobbs@gmail.com - 2017-02-10 10:23 -0800
      Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 11:16 -0800
        Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 11:27 -0800
        Re: An old "500MC biquinary counter" pcdhobbs@gmail.com - 2017-02-10 12:32 -0800
          Re: An old "500MC biquinary counter" bill.sloman@ieee.org - 2017-02-10 16:05 -0800
          Re: An old "500MC biquinary counter" "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-11 10:28 -0600
    Re: An old "500MC biquinary counter" Piglet <erichpwagner@hotmail.com> - 2017-02-10 20:32 +0000
      Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 13:26 -0800
        Re: An old "500MC biquinary counter" Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-10 12:50 -0500
          Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 14:55 -0800
            Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) Dave M <dgminala at mediacombb dot net> - 2017-02-10 18:41 -0600
              Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) "Dave M" <dgminala@mediacombb.net> - 2017-02-10 18:50 -0600
                Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) Joerg <news@analogconsultants.com> - 2017-02-10 16:58 -0800
                Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) Clifford Heath <no.spam@please.net> - 2017-02-11 14:29 +1100
                Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) whit3rd <whit3rd@gmail.com> - 2017-02-11 02:48 -0800
            Re: An old "500MC biquinary counter" Piglet <erichpwagner@hotmail.com> - 2017-02-11 11:00 +0000
          Re: An old "500MC biquinary counter" "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> - 2017-02-11 20:57 -0500
            Re: An old "500MC biquinary counter" krw@notreal.com - 2017-02-11 22:07 -0500
            Re: An old "500MC biquinary counter" Clifford Heath <no.spam@please.net> - 2017-02-12 18:21 +1100
              Re: An old "500MC biquinary counter" krw@notreal.com - 2017-02-12 17:04 -0500
      Re: An old "500MC biquinary counter" Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 14:40 -0700
        Re: An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-10 17:59 -0500
        Re: An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-10 18:04 -0500
          Re: An old "500MC biquinary counter" dagmargoodboat@yahoo.com - 2017-02-11 06:41 -0800
  Re: An old "500MC biquinary counter" rickman <gnuarm@gmail.com> - 2017-02-11 07:10 -0500
    Re: An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-11 11:36 -0500

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