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An old "500MC biquinary counter"

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  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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#447169 — An old "500MC biquinary counter"

What are D1-D5?

http://www.seekic.com/uploadfile/ic-circuit/s2009713233931554.gif

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#447175

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.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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#447186

"Joerg" <news@analogconsultants.com> wrote in message 
news:eg6ag4Fig75U1@mid.individual.net...
> 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.
>
> -- 
> Regards, Joerg
>
> http://www.analogconsultants.com/

Tunnel diodes.

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#447193

On Fri, 10 Feb 2017 13:24:10 -0500, "tom" <tmiller11147@verizon.net>
wrote:

>
>"Joerg" <news@analogconsultants.com> wrote in message 
>news:eg6ag4Fig75U1@mid.individual.net...
>> 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.
>>
>> -- 
>> Regards, Joerg
>>
>> http://www.analogconsultants.com/
>
>Tunnel diodes.
>

I still have a bunch of TDs. Haltek had a bin full and didn't know
what they were, so I got them for 10 cents each.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#447205

>I still have a bunch of TDs. Haltek had a bin full and didn't know 
>what they were, so I got them for 10 cents each. 

Nice. I got a bunch off eBay, but they're only 10 mA peak current so they're not that fast. The quick ones are the 200 mA types. 

Cheers

Phil Hobbs

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#447215

On Fri, 10 Feb 2017 12:36:17 -0800 (PST), pcdhobbs@gmail.com wrote:

>>I still have a bunch of TDs. Haltek had a bin full and didn't know 
>>what they were, so I got them for 10 cents each. 
>
>Nice. I got a bunch off eBay, but they're only 10 mA peak current so they're not that fast. The quick ones are the 200 mA types. 
>
>Cheers
>
>Phil Hobbs

Yeah, mine are 5 or maybe 10 mA, nanosecond rise times. The high
current stripline parts from RCA and GE got down to 25 ps rise times,
in maybe 1963. I have the 1963 RCA Tunnel Diode Manual!

http://swissen.in/support_images/Electronics/Tunnel%20Diode/tunnel%20diode%20construction.png

Basically, you etch away Ge and make the diode tinier and tinier,
until you can't any more.

http://www.radio-electronics.com/info/data/semicond/tunneldiode/tunnel-diode-structure-ball-alloy.gif


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#447216

On 02/10/2017 05:15 PM, John Larkin wrote:
> On Fri, 10 Feb 2017 12:36:17 -0800 (PST), pcdhobbs@gmail.com wrote:
>
>>> I still have a bunch of TDs. Haltek had a bin full and didn't
>>> know what they were, so I got them for 10 cents each.
>>
>> Nice. I got a bunch off eBay, but they're only 10 mA peak current
>> so they're not that fast. The quick ones are the 200 mA types.
>>
>> Cheers
>>
>> Phil Hobbs
>
> Yeah, mine are 5 or maybe 10 mA, nanosecond rise times. The high
> current stripline parts from RCA and GE got down to 25 ps rise
> times, in maybe 1963. I have the 1963 RCA Tunnel Diode Manual!
>
> http://swissen.in/support_images/Electronics/Tunnel%20Diode/tunnel%20diode%20construction.png
>
>  Basically, you etch away Ge and make the diode tinier and tinier,
> until you can't any more.
>
> http://www.radio-electronics.com/info/data/semicond/tunneldiode/tunnel-diode-structure-ball-alloy.gif
>
But even the fastest ones have crazy amounts of capacitance because 
they're still huge and the depletion zone is so thin because of the 
ridiculously high doping.

I have some Russian GaAs ones on my desk that I'll have to try out. 
They're in a beam-lead package. (It's like 2 inches worth of beam lead, 
but flat, so they must be fast). ;)

Cheers

Phil Hobbs

Cheers

Phil Hobbs


-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

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#447243

On Fri, 10 Feb 2017 13:16:20 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 02/10/2017 05:15 PM, John Larkin wrote:
>> On Fri, 10 Feb 2017 12:36:17 -0800 (PST), pcdhobbs@gmail.com wrote:
>>
>>>> I still have a bunch of TDs. Haltek had a bin full and didn't
>>>> know what they were, so I got them for 10 cents each.
>>>
>>> Nice. I got a bunch off eBay, but they're only 10 mA peak current
>>> so they're not that fast. The quick ones are the 200 mA types.
>>>
>>> Cheers
>>>
>>> Phil Hobbs
>>
>> Yeah, mine are 5 or maybe 10 mA, nanosecond rise times. The high
>> current stripline parts from RCA and GE got down to 25 ps rise
>> times, in maybe 1963. I have the 1963 RCA Tunnel Diode Manual!
>>
>> http://swissen.in/support_images/Electronics/Tunnel%20Diode/tunnel%20diode%20construction.png
>>
>>  Basically, you etch away Ge and make the diode tinier and tinier,
>> until you can't any more.
>>
>> http://www.radio-electronics.com/info/data/semicond/tunneldiode/tunnel-diode-structure-ball-alloy.gif
>>
>But even the fastest ones have crazy amounts of capacitance because 
>they're still huge and the depletion zone is so thin because of the 
>ridiculously high doping.
>
>I have some Russian GaAs ones on my desk that I'll have to try out. 
>They're in a beam-lead package. (It's like 2 inches worth of beam lead, 
>but flat, so they must be fast). ;)
>
>Cheers
>
>Phil Hobbs
>
>Cheers
>
>Phil Hobbs


The RCA 40079 had Ip of 200 amps, Cj = 1.25 uF, Rj = 1 mohm, Tr = 4
ns, 1" diameter stud package.

TDs were fun.

Do Russians still make TDs?



 
-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#447244

On 02/10/2017 07:14 PM, John Larkin wrote:
> On Fri, 10 Feb 2017 13:16:20 -0500, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>> On 02/10/2017 05:15 PM, John Larkin wrote:
>>> On Fri, 10 Feb 2017 12:36:17 -0800 (PST), pcdhobbs@gmail.com wrote:
>>>
>>>>> I still have a bunch of TDs. Haltek had a bin full and didn't
>>>>> know what they were, so I got them for 10 cents each.
>>>>
>>>> Nice. I got a bunch off eBay, but they're only 10 mA peak current
>>>> so they're not that fast. The quick ones are the 200 mA types.
>>>>
>>>> Cheers
>>>>
>>>> Phil Hobbs
>>>
>>> Yeah, mine are 5 or maybe 10 mA, nanosecond rise times. The high
>>> current stripline parts from RCA and GE got down to 25 ps rise
>>> times, in maybe 1963. I have the 1963 RCA Tunnel Diode Manual!
>>>
>>> http://swissen.in/support_images/Electronics/Tunnel%20Diode/tunnel%20diode%20construction.png
>>>
>>>  Basically, you etch away Ge and make the diode tinier and tinier,
>>> until you can't any more.
>>>
>>> http://www.radio-electronics.com/info/data/semicond/tunneldiode/tunnel-diode-structure-ball-alloy.gif
>>>
>> But even the fastest ones have crazy amounts of capacitance because
>> they're still huge and the depletion zone is so thin because of the
>> ridiculously high doping.
>>
>> I have some Russian GaAs ones on my desk that I'll have to try out.
>> They're in a beam-lead package. (It's like 2 inches worth of beam lead,
>> but flat, so they must be fast). ;)
>>
>> Cheers
>>
>> Phil Hobbs
>>
>> Cheers
>>
>> Phil Hobbs
>
>
> The RCA 40079 had Ip of 200 amps, Cj = 1.25 uF, Rj = 1 mohm, Tr = 4
> ns, 1" diameter stud package.
>
> TDs were fun.
>
> Do Russians still make TDs?
>
>
>
>
>
Dunno.  You can get these weird pseudo beam-lead things that they claim 
are GaAs TDs, but probably the factory shut down long ago.

Given the excesses of deranged central planners (but I repeat myself), 
it might take awhile to sell off the backlog 10 at a time on eBay. ;)

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

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#447187

Maybe tunnel diodes forming the storage latches. 

Cheers

Phil Hobbs

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#447188

On 2017-02-10 10:23, pcdhobbs@gmail.com wrote:
> Maybe tunnel diodes forming the storage latches.
>

AFAIU this is an IC. Has there been a process that could integrate those?

-- 
Regards, Joerg

http://www.analogconsultants.com/

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#447192

On Fri, 10 Feb 2017 11:16:58 -0800, Joerg <news@analogconsultants.com>
wrote:

>On 2017-02-10 10:23, pcdhobbs@gmail.com wrote:
>> Maybe tunnel diodes forming the storage latches.
>>
>
>AFAIU this is an IC. Has there been a process that could integrate those?

Not that I know of. TDs were hand-welded and etched, a truly bizarre
fab process.

The only photolithographically-formed germanium devices that I've
heard of are back diodes, essentially TDs with very low peak point
current, still used as RF detector and mixer diodes.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#447204

>AFAIU this is an IC. Has there been a process that could integrate those?

Maybe in GaAs, but not Ge, I'm pretty sure. Besides leakage, Ge isn't suitable for normal planar processing--its oxide is only slightly better than carbon's. ;)

Cheers

Phil Hobbs

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#447242

On Saturday, February 11, 2017 at 7:33:02 AM UTC+11, pcdh...@gmail.com wrote:
> >AFAIU this is an IC. Has there been a process that could integrate those?
> 
> Maybe in GaAs, but not Ge, I'm pretty sure. Besides leakage, Ge isn't suitable for normal planar processing--its oxide is only slightly better than carbon's. ;)

GeO2 may not insulate as well as SiO2, but it's less volatile than CO2 - it melts at 1,115 °C (2,039 °F; 1,388 K).

As a greenhouse gas, it's not going to be a problem for a few billion years.

-- 
Bill Sloman, Sydney

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#447297

<pcdhobbs@gmail.com> wrote in message 
news:e53b3b28-4e3b-4761-a440-248a4c239c79@googlegroups.com...
> >AFAIU this is an IC. Has there been a process that could integrate those?
>
> Maybe in GaAs, but not Ge, I'm pretty sure. Besides leakage, Ge isn't 
> suitable for normal planar processing--its oxide is only slightly better 
> than carbon's. ;)
>

Hey! At >10GPa, CO2 is as good as SiO2 or GeO2, so there!

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com 

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#447203

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.

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.


piglet

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#447208

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/

[toc] | [prev] | [next] | [standalone]

#447213

On 02/10/2017 04:26 PM, Joerg wrote:
> 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.
>

Well, it does say "500MC biquinary counter". ;)

I suspect it was never an actual IC.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[toc] | [prev] | [next] | [standalone]

#447222

On 2017-02-10 09:50, Phil Hobbs wrote:
> On 02/10/2017 04:26 PM, Joerg wrote:
>> 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.
>>
>
> Well, it does say "500MC biquinary counter". ;)
>
> I suspect it was never an actual IC.
>

With 2k resistors and stuff in there it would never even get into the 
VHF range :-)

-- 
Regards, Joerg

http://www.analogconsultants.com/

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#447247 — Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1)

On Fri, 10 Feb 2017 14:55:27 -0800, Joerg <news@analogconsultants.com>
wrote:

>On 2017-02-10 09:50, Phil Hobbs wrote:
>> On 02/10/2017 04:26 PM, Joerg wrote:
>>> 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.
>>>
>>
>> Well, it does say "500MC biquinary counter". ;)
>>
>> I suspect it was never an actual IC.
>>
>
>With 2k resistors and stuff in there it would never even get into the 
>VHF range :-)


Here's a copy of the circuit as it appeared in Electronics magazine back
in 1966.  The diodes are 1N752A Zeners.   It's redrawn here so it's
easier to understand.  Just a divide-by-5 ring counter.  Looks like the
Zeners are there to protect the B-E junctions of the right-hand
transistor of each stage.

Cheers,
Dave M

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