https://www.microwavejournal.com/articles/45122-the-design-of-very-narrowband-tunnel-diode-negative-resistance-amplifiers
I got excited to see this article, until I realized that they used an >obsolete germanium tunnel diode from an old-parts dealer.
Pity. I liked tunnel diodes.
On Wed, 07 Jan 2026 08:07:26 -0800, john larkin <jl@glen--canyon.com>
wrote:
https://www.microwavejournal.com/articles/45122-the-design-of-very-narrowband-tunnel-diode-negative-resistance-amplifiers
I got excited to see this article, until I realized that they used an >>obsolete germanium tunnel diode from an old-parts dealer.
Pity. I liked tunnel diodes.
.<https://www.americanmicrosemi.com/product/1N3716/>
Only $97.
Joe
john larkin <jl@glen--canyon.com>wrote:
https://www.microwavejournal.com/articles/45122-the-design-of-very-narrowband-tunnel-diode-negative-resistance-amplifiers
I got excited to see this article, until I realized that they used an >obsolete germanium tunnel diode from an old-parts dealer.
Pity. I liked tunnel diodes.
john larkin <jl@glen--canyon.com>wrote:
https://www.microwavejournal.com/articles/45122-the-design-of-very-narrowband-tunnel-diode-negative-resistance-amplifiers
I got excited to see this article, until I realized that they used an >>obsolete germanium tunnel diode from an old-parts dealer.
Pity. I liked tunnel diodes.
I have a tunnel diode from ebay somewhere
https://www.ebay.com/sch/i.html?_nkw=tunnel+diode
On Thu, 08 Jan 2026 04:27:25 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
john larkin <jl@glen--canyon.com>wrote:
https://www.microwavejournal.com/articles/45122-the-design-of-very-narrowband-tunnel-diode-negative-resistance-amplifiers
I got excited to see this article, until I realized that they used an
obsolete germanium tunnel diode from an old-parts dealer.
Pity. I liked tunnel diodes.
I have a tunnel diode from ebay somewhere
https://www.ebay.com/sch/i.html?_nkw=tunnel+diode
Yikes. I paid 10 cents for mine.
But modern ICs are mostly faster these days.
john larkin <jl@glen--canyon.com> wrote:
On Thu, 08 Jan 2026 04:27:25 GMT, Jan Panteltje <alien@comet.invalid>Lower power, too. Old Ge TDs have about 200 pF junction capacitance, so to >get any speed you need a very high peak current, at least 100 mA.
wrote:
john larkin <jl@glen--canyon.com>wrote:
https://www.microwavejournal.com/articles/45122-the-design-of-very-narrowband-tunnel-diode-negative-resistance-amplifiers
I got excited to see this article, until I realized that they used an
obsolete germanium tunnel diode from an old-parts dealer.
Pity. I liked tunnel diodes.
I have a tunnel diode from ebay somewhere
https://www.ebay.com/sch/i.html?_nkw=tunnel+diode
Yikes. I paid 10 cents for mine.
But modern ICs are mostly faster these days.
Cheers
Phil Hobbs
On Thu, 8 Jan 2026 13:09:53 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Thu, 08 Jan 2026 04:27:25 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
john larkin <jl@glen--canyon.com>wrote:
The best bang per buck these days, for sub-ns steps, is probably some
cmos gates and some laser drivers. Or SRDs.
Somebody orter write a book about making fast pulses, a modern version
of Millimicrosecond Pulse Techniques.
https://www.amazon.com/Millimicrosecond-Pulse-Techniques-International-Instrumentation/dp/1483119912?s=books
On 9/01/2026 3:17 am, john larkin wrote:
On Thu, 8 Jan 2026 13:09:53 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Thu, 08 Jan 2026 04:27:25 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
john larkin <jl@glen--canyon.com>wrote:
The best bang per buck these days, for sub-ns steps, is probably some
cmos gates and some laser drivers. Or SRDs.
Somebody orter write a book about making fast pulses, a modern version
of Millimicrosecond Pulse Techniques.
https://www.amazon.com/Millimicrosecond-Pulse-Techniques-International-Instrumentation/dp/1483119912?s=books
Step recovery diodes have the problem that you have to set up the
forward current, and then reverse bias the diode, and you don't get the >step-recovery until you have swept out the charge carriers, and that
takes a while.
ECL was much more predictable. You needed wide band transistors to get
any sort of voltage swing out of the transitions, but it was all a lot
more designable.
Fast CMOS puts a lot of noise on the power rails, and that can be a real >nuisance. I used a Percival distributed amplifier to get a pair of >complementary 800psec wide +/-5V pulses which was reliable enough to
ship, but a simpler circuit with bigger transistors gave us 500psec, so
we settled on that.
I suspect that the Percival circuit would gone faster with slightly
bigger wide-band transistors, but 500psec was good enough.
On Mon, 12 Jan 2026 01:10:53 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 9/01/2026 3:17 am, john larkin wrote:
On Thu, 8 Jan 2026 13:09:53 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Thu, 08 Jan 2026 04:27:25 GMT, Jan Panteltje <alien@comet.invalid> >>>>> wrote:
john larkin <jl@glen--canyon.com>wrote:
The best bang per buck these days, for sub-ns steps, is probably some
cmos gates and some laser drivers. Or SRDs.
Somebody orter write a book about making fast pulses, a modern version
of Millimicrosecond Pulse Techniques.
https://www.amazon.com/Millimicrosecond-Pulse-Techniques-International-Instrumentation/dp/1483119912?s=books
Step recovery diodes have the problem that you have to set up the
forward current, and then reverse bias the diode, and you don't get the >>step-recovery until you have swept out the charge carriers, and that
takes a while.
ECL was much more predictable. You needed wide band transistors to get
any sort of voltage swing out of the transitions, but it was all a lot >>more designable.
Fast CMOS puts a lot of noise on the power rails, and that can be a real >>nuisance. I used a Percival distributed amplifier to get a pair of >>complementary 800psec wide +/-5V pulses which was reliable enough to
ship, but a simpler circuit with bigger transistors gave us 500psec, so
we settled on that.
I suspect that the Percival circuit would gone faster with slightly
bigger wide-band transistors, but 500psec was good enough.
Distributed amps are great for making big fast swings, but
They are AC coupled
Inefficient
Hard to bias
Cost hundreds of dollars each
This uses an HMC659 distributed amp (slow, only 15 GHz) to make 8 volt
pulses into an e/o modulator. The chip costs us $300 each.
https://www.dropbox.com/scl/fi/blea3ca66pw16hbngnwa5/T502B6-316.jpg?rlkey=d7osnlzw9m30ttyoedrvj25er&raw=1
This is rev B. It only too TWO tries to get this right.
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
...My typing is really bad lately. I blame the chair.
john larkin <jl@glen--canyon.com> wrote:
[...]
...My typing is really bad lately. I blame the chair.
Yes, I find it is so difficult to get it at the right height for my
toes to reach the keyboard.
On Mon, 12 Jan 2026 01:10:53 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 9/01/2026 3:17 am, john larkin wrote:
On Thu, 8 Jan 2026 13:09:53 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Thu, 08 Jan 2026 04:27:25 GMT, Jan Panteltje <alien@comet.invalid> >>>>> wrote:
john larkin <jl@glen--canyon.com>wrote:
The best bang per buck these days, for sub-ns steps, is probably some
cmos gates and some laser drivers. Or SRDs.
Somebody orter write a book about making fast pulses, a modern version
of Millimicrosecond Pulse Techniques.
https://www.amazon.com/Millimicrosecond-Pulse-Techniques-International-Instrumentation/dp/1483119912?s=books
Step recovery diodes have the problem that you have to set up the
forward current, and then reverse bias the diode, and you don't get the
step-recovery until you have swept out the charge carriers, and that
takes a while.
ECL was much more predictable. You needed wide band transistors to get
any sort of voltage swing out of the transitions, but it was all a lot
more designable.
Fast CMOS puts a lot of noise on the power rails, and that can be a real
nuisance. I used a Percival distributed amplifier to get a pair of
complementary 800psec wide +/-5V pulses which was reliable enough to
ship, but a simpler circuit with bigger transistors gave us 500psec, so
we settled on that.
I suspect that the Percival circuit would gone faster with slightly
bigger wide-band transistors, but 500psec was good enough.
Distributed amps are great for making big fast swings, but
They are AC coupled
Inefficient
Hard to bias
Cost hundreds of dollars each.
This uses an HMC659 distributed amp (slow, only 15 GHz) to make 8 volt
pulses into an e/o modulator. The chip costs us $300 each.
https://www.dropbox.com/scl/fi/blea3ca66pw16hbngnwa5/T502B6-316.jpg?rlkey=d7osnlzw9m30ttyoedrvj25er&raw=1
This is rev B. It only took TWO tries to get this right.
On 12/01/2026 3:20 am, john larkin wrote:
On Mon, 12 Jan 2026 01:10:53 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 9/01/2026 3:17 am, john larkin wrote:
On Thu, 8 Jan 2026 13:09:53 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Thu, 08 Jan 2026 04:27:25 GMT, Jan Panteltje <alien@comet.invalid> >>>>>> wrote:
john larkin <jl@glen--canyon.com>wrote:
The best bang per buck these days, for sub-ns steps, is probably some >>>> cmos gates and some laser drivers. Or SRDs.
Somebody orter write a book about making fast pulses, a modern version >>>> of Millimicrosecond Pulse Techniques.
https://www.amazon.com/Millimicrosecond-Pulse-Techniques-International-Instrumentation/dp/1483119912?s=books
Step recovery diodes have the problem that you have to set up the
forward current, and then reverse bias the diode, and you don't get the
step-recovery until you have swept out the charge carriers, and that
takes a while.
ECL was much more predictable. You needed wide band transistors to get
any sort of voltage swing out of the transitions, but it was all a lot
more designable.
Fast CMOS puts a lot of noise on the power rails, and that can be a real >>> nuisance. I used a Percival distributed amplifier to get a pair of
complementary 800psec wide +/-5V pulses which was reliable enough to
ship, but a simpler circuit with bigger transistors gave us 500psec, so
we settled on that.
I suspect that the Percival circuit would gone faster with slightly
bigger wide-band transistors, but 500psec was good enough.
Distributed amps are great for making big fast swings, but
They are AC coupled
Mine wasn't.
Inefficient
Mine wasn't.
Hard to bias
Mine wasn't.
Cost hundreds of dollars each.
Mine certainly didn't. It was cheaper than the simpler big transistor
device that replaced it.
None of your claims are backed up by the Wikipedia entry
https://en.wikipedia.org/wiki/Distributed_amplifier
I once talked with William S. Percival when I was working at EMI Central >Research around 1977 - he was still working there, and still remarkably >clever. I couldn't tell him what he wanted to know, but it was an >interesting conversation.
This uses an HMC659 distributed amp (slow, only 15 GHz) to make 8 volt
pulses into an e/o modulator. The chip costs us $300 each.
https://www.analog.com/en/products/hmc659-die.html
https://www.dropbox.com/scl/fi/blea3ca66pw16hbngnwa5/T502B6-316.jpg?rlkey=d7osnlzw9m30ttyoedrvj25er&raw=1
Not the most informative of images, and the data sheet wasn't all that >informative either
This is rev B. It only took TWO tries to get this right.
"Right"? You mean that your second attempt worked well enough to let you >sell it.
Granting bizarre the claims you've just made about distributed
amplifiers this is improbably quick. The Analog Devices part must be
well designed.
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