TO can package parasitics...

P

Phil Hobbs

Guest
Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

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
 
On 2021/11/29 9:58 a.m., Phil Hobbs wrote:
Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs
Click to expand...

Have you checked bitsavers.org or archive.org? Al Kossow has sent
archive.org a lot of his scanned parts catalogues and reference manuals.
Easier to find on bitsavers though...

John :-#)#
 
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs
Click to expand...

Can you TDR one?

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
 
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs
Click to expand...

You sure you mean TO-8 ?

TO-8 is a package that was used almost exclusively
for power germanium parts.

RL
 
legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You sure you mean TO-8 ?

TO-8 is a package that was used almost exclusively
for power germanium parts.

RL
Click to expand...

Yup.

And a whole lot of larger-size optical detectors that aren\'t passivated
well enough for non-hermetic packages.

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
 
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs
Click to expand...

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL
 
John Larkin wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

Can you TDR one?
Click to expand...

I could if I had one handy, but ATM I\'m dealing with a requirement to
make a front end with ~ 350 MHz BW from a TO-8.

12 pF and 5 nH resonate at 650 MHz, so you see the issue.

I\'m trying to decide whether to have a go at it or insist on the goal
posts being moved.

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
 
On Mon, 29 Nov 2021 20:06:25 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You sure you mean TO-8 ?

TO-8 is a package that was used almost exclusively
for power germanium parts.

RL


Yup.

And a whole lot of larger-size optical detectors that aren\'t passivated
well enough for non-hermetic packages.
Click to expand...

https://www.dropbox.com/s/wm3a3cpxa8tcarg/S8551_1.JPG?raw=1

I could TDR that one, but it\'s a TO5.


--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
 
legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

Thanks, Rob.
Click to expand...

Cheers

Phil

--
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
 
On Tue, 30 Nov 2021 13:07:03 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

Thanks, Rob.

Cheers

Phil
Click to expand...

Any idea why gold-plated kovar would reduce inductance by factor of
3:1 ?

RL
 
On Tuesday, 30 November 2021 at 19:34:24 UTC, legg wrote:
On Tue, 30 Nov 2021 13:07:03 -0500, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

Thanks, Rob.

Cheers

Phil
Any idea why gold-plated kovar would reduce inductance by factor of
3:1 ?

RL
Click to expand...

Maybe they got the decimal point in the wrong place. Otherwise it doesn\'t make sense.
John
 
legg wrote:
On Tue, 30 Nov 2021 13:07:03 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

Thanks, Rob.

Cheers

Phil

Any idea why gold-plated kovar would reduce inductance by factor of
3:1 ?

RL
Click to expand...
Probably just closer to the baseplate--reduces loop area. Or it could
be wrong. ;)

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
 
On 01/12/2021 06:31, legg wrote:
On Tue, 30 Nov 2021 13:07:03 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

Thanks, Rob.

Cheers

Phil

Any idea why gold-plated kovar would reduce inductance by factor of
3:1 ?

RL
Click to expand...

I think kovar is magnetic, perhaps that would make a difference, at
least at some frequencies.
 
On Mon, 29 Nov 2021 20:04:11 -0500, legg <legg@nospam.magma.ca> wrote:

On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL
Click to expand...

I\'ve seen butterfly package lasers with a long wirebond from the pin
to the laser chip, and some with a ceramic transmission line ramp
sloping down to the chip.

https://www.dropbox.com/s/4g9ac2x7nz20pos/Butterfly_ebay_Dyno1.jpg?raw=1



--

Father Brown\'s figure remained quite dark and still;
but in that instant he had lost his head. His head was
always most valuable when he had lost it.
 
On Tue, 30 Nov 2021 20:28:01 -0800, jlarkin@highlandsniptechnology.com
wrote:

On Mon, 29 Nov 2021 20:04:11 -0500, legg <legg@nospam.magma.ca> wrote:

On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

I\'ve seen butterfly package lasers with a long wirebond from the pin
to the laser chip, and some with a ceramic transmission line ramp
sloping down to the chip.

https://www.dropbox.com/s/4g9ac2x7nz20pos/Butterfly_ebay_Dyno1.jpg?raw=1
Click to expand...

TL or just and SMD link?

https://www.knowlescapacitors.com/Products/Thin-Film-and-Substrates/Mounting-Shorts

Doesn\'t help if the canned part is prescribed.

RL
 
On Wed, 1 Dec 2021 14:14:31 +1100, Chris Jones
<lugnut808@spam.yahoo.com> wrote:

On 01/12/2021 06:31, legg wrote:
On Tue, 30 Nov 2021 13:07:03 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

Thanks, Rob.

Cheers

Phil

Any idea why gold-plated kovar would reduce inductance by factor of
3:1 ?

RL


I think kovar is magnetic, perhaps that would make a difference, at
least at some frequencies.
Click to expand...

.. . . any increase in permeability in the neighborhood could be
expected to make things worse, not better.

RL
 
legg wrote:
On Wed, 1 Dec 2021 14:14:31 +1100, Chris Jones
lugnut808@spam.yahoo.com> wrote:

On 01/12/2021 06:31, legg wrote:
On Tue, 30 Nov 2021 13:07:03 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

legg wrote:
On Mon, 29 Nov 2021 12:58:42 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Hi, all,

I need to build a fast front end for a fairly huge photodiode--2 mm
square, 12 pF, TO-8 can package.

The TO-8 has a pin spacing of 0.2 inch, so based on the usual
20-nH-per-inch rule of thumb, I expect its package inductance to come in
at 5 nH or thereabouts.

I looked around on the Web for some table of parasitics for varioius
packages, but didn\'t find anything that included old-timey packages such
as metal cans.

Does anybody have such a reference handy?

Thanks

Phil Hobbs

You might compare it to some laser diode packages for Mech/Elec
strays.

https://picolas.de/wp-content/uploads/2020/08/Application-Note-02_Impedance-of-Diodes_Bt03_tk01_sl02_am_HL_jhs2_asz.pdf

RL

Thanks, Rob.

Cheers

Phil

Any idea why gold-plated kovar would reduce inductance by factor of
3:1 ?

RL


I think kovar is magnetic, perhaps that would make a difference, at
least at some frequencies.

. . . any increase in permeability in the neighborhood could be
expected to make things worse, not better.
Click to expand...

Depends on the frequency. Up at UHF the skin depth in the kovar will be
zilch, and the permeability will be pretty small anyway--it goes to 1.0
around 500 MHz for most iron/nickel alloys AFAICT.

A quick search didn\'t turn up anything more recent than this:

<https://www.nature.com/articles/162528a0.pdf> (open access).

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
 
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