Reply by John Larkin ●February 16, 20122012-02-16
On Wed, 15 Feb 2012 19:48:02 +0100, Fred Bartoli <" "> wrote:


>John Larkin a &#4294967295;crit :
>> On Mon, 13 Feb 2012 20:03:34 -0800, Robert Baer
>> <robertbaer@localnet.com> wrote:
>> 
>>> Phil Hobbs wrote:
>>>> On 02/13/2012 03:12 AM, Okkim Atnarivik wrote:
>>>>> Phil Hobbs<pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>>> : I started by taking your advice, which was pretty valuable--thanks
>>>>>
>>>>> Don't mention it. I have already gained more from your, Larkin's,
>>>>> Win Hill's and many other's posts here in SED.
>>>>>
>>>>> : again. I noticed the change in specs as well, when I ordered another
>>>>> : batch a couple of months ago. They changed the type number to BFP650H
>>>>> : instead of BFP650E when they changed the process. (The dogs.)
>>>>>
>>>>> They did? The datasheet still list the part as BFP650 without suffixes
>>>>> even though it is the SiGe:C version.
>>>> The distributors' stock of the E version all ran out a few months ago,
>>>> and all they have now is the H version. I haven't managed to get the
>>>> straight story as to just what they did.
>>>>
>>>>> : I'm using it as a cascode stage for a SKY65050 pHEMT, and it works
>>>>>
>>>>> Interesting hint, I should give it a try.
>>>>>
>>>>> : great. One of the best things about it is that it has effectively
>>>>> : infinite Early voltage, so you can get a lot of voltage gain out of a
>>>>> : single stage. Even for situations where you don't care so much about
>>>>> : ultralow noise, the combination of a gigantic f_T with a very high V_A
>>>>> : is unique in my collection. It does want to oscillate at 14 GHz if you
>>>>> : look at it crosswise, but a nice 5-ohm bead in series with the base
>>>>> : cleans that right up.
>>>>>
>>>>> The high Early seems to be characteristic to the SiGe's, it puzzled me
>>>>> already in the thread http://tinyurl.com/8a44pzn . If you check the
>>>>> page 4 of http://tinyurl.com/6qmnd4u you see it there too (and
>>>>> additionally
>>>>> you get the large hFE = 400 ).
>>>> I've ordered some of those too, thanks. It's a bit worrying that there
>>>> are seem to be only about 100 of them in the world, according to FindChips.
>>>>
>>>> Cheers
>>>>
>>>> Phil
>>>>> Regards,
>>>>> Mikko
>>>>
>>>   Oh..i like that non-functional circuit on page two..
>> 
>> Wow, that's pretty bad.
>> 
>
>And the comments above the wonderful circuit is pretty bad as well...
>
>


Yeah, could you please translate that into English for us?


-- 

John Larkin, President       Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
Reply by John Larkin ●February 15, 20122012-02-15
On Wed, 15 Feb 2012 20:48:02 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
wrote:


>On 02/15/2012 03:55 PM, John Larkin wrote:
>
>> Loops in the PCB trace layout will be better magnetic pickups than a
>> ferrite bead.
>>
>
>Especially if there are unrelated pieces of ferrite sitting inside
>the loop, yelling "All you fluxes, come here, here is a well-paved
>road".
>
>


A surface-mount ferrite bead is not much magnetic volume. I don't know
how they are constructed, but I don't think they are coils... maybe
just serpentines. Beads typically have a few uH of base indictance.

http://www.vishay.com/docs/ilb_ilbb_enote.pdf

This claims that beads are "closed magnetic circuits" and "inherently
shielded."


-- 

John Larkin, President
Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation
Reply by Gerhard Hoffmann ●February 15, 20122012-02-15
On 02/15/2012 03:55 PM, John Larkin wrote:


> Loops in the PCB trace layout will be better magnetic pickups than a
> ferrite bead.
>


Especially if there are unrelated pieces of ferrite sitting inside
the loop, yelling "All you fluxes, come here, here is a well-paved
road".
Reply by John Larkin ●February 15, 20122012-02-15
On Wed, 15 Feb 2012 17:38:38 GMT, nico@puntnl.niks (Nico Coesel)
wrote:


>Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>>On 02/14/2012 04:41 PM, John Larkin wrote:
>>> On Tue, 14 Feb 2012 18:46:18 +0100, Gerhard Hoffmann<dk4xp@arcor.de>
>>> wrote:
>>>
>>>> On 02/14/2012 04:16 PM, John Larkin wrote:
>>>>> On Tue, 14 Feb 2012 08:56:40 +0100, Gerhard Hoffmann<dk4xp@arcor.de>
>>>>> wrote:
>>>>>
>>>>>> On 02/14/2012 01:22 AM, BobW wrote:
>>>>>>
>>>>>>> We're looking at the latest LeCroy scopes to look at 37GHz signals.
>>>>>>> Their new 10 series has up to 60GHz of bandwidth and 160GSamples/s (real
>>>>>>> time). It's only about $400K :-|. They use 2.4mm connectors. I'm not
>>>>>>> sure if you can get a direct MMPX<->2.4mm without adapters.
>>>>>>
>>>>>> In december, we had one of these 80 GSPS real time thingies from Agilent
>>>>>> for a week to test, made me quite greedy.
>>>>>>
>>>>>> Gerhard
>>>>>
>>>>> I have a Tek 11801 sampler with a 40 GHz head. Costs about $2K on
>>>>> ebay.
>>>>
>>>>
>>>> That was at my customer's.
>>>>
>>>> I myself have a hp54750a with 20 and 50 GHz plug-ins, 9 ps risetime.
>>>> But it is not real-time. One cannot trigger on the one bit error in
>>>> a 10 GB/s fiber optic link that may or may not happen this night.
>>>>
>>>> 5 years ago, we could have been faster by 6 weeks during the
>>>> development of a XFP transceiver.
>>>
>>> A realtime scope would be handy around here for snooping PCI Express
>>> signals. Maybe pricing for a, say, 4 GHz scope (with probes!) will get
>>> reasonable some day.
>>>
>>>
>>You can get a TDS694 for $5k-ish.  3 GHz, 10 Gs/s.
>
>Thats way too expensive for such an old scope. I strongly doubt you
>can actually use this scope at 3GHz. It has BNC inputs (where most
>other equipment uses N or SMB for anything over 500MHz). There several
>offered on Ebay but they are not getting sold for 5k.


BNCs work fine at 3 GHz. But you'd need active probes in a lot of
situations, like snooping serial busses, and they can get expensive.


-- 

John Larkin, President
Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation
Reply by Phil Hobbs ●February 15, 20122012-02-15
On 02/15/2012 12:38 PM, Nico Coesel wrote:

> Phil Hobbs<pcdhSpamMeSenseless@electrooptical.net>  wrote:
>
>> On 02/14/2012 04:41 PM, John Larkin wrote:
>>> On Tue, 14 Feb 2012 18:46:18 +0100, Gerhard Hoffmann<dk4xp@arcor.de>
>>> wrote:
>>>
>>>> On 02/14/2012 04:16 PM, John Larkin wrote:
>>>>> On Tue, 14 Feb 2012 08:56:40 +0100, Gerhard Hoffmann<dk4xp@arcor.de>
>>>>> wrote:
>>>>>
>>>>>> On 02/14/2012 01:22 AM, BobW wrote:
>>>>>>
>>>>>>> We're looking at the latest LeCroy scopes to look at 37GHz signals.
>>>>>>> Their new 10 series has up to 60GHz of bandwidth and 160GSamples/s (real
>>>>>>> time). It's only about $400K :-|. They use 2.4mm connectors. I'm not
>>>>>>> sure if you can get a direct MMPX<->2.4mm without adapters.
>>>>>>
>>>>>> In december, we had one of these 80 GSPS real time thingies from Agilent
>>>>>> for a week to test, made me quite greedy.
>>>>>>
>>>>>> Gerhard
>>>>>
>>>>> I have a Tek 11801 sampler with a 40 GHz head. Costs about $2K on
>>>>> ebay.
>>>>
>>>>
>>>> That was at my customer's.
>>>>
>>>> I myself have a hp54750a with 20 and 50 GHz plug-ins, 9 ps risetime.
>>>> But it is not real-time. One cannot trigger on the one bit error in
>>>> a 10 GB/s fiber optic link that may or may not happen this night.
>>>>
>>>> 5 years ago, we could have been faster by 6 weeks during the
>>>> development of a XFP transceiver.
>>>
>>> A realtime scope would be handy around here for snooping PCI Express
>>> signals. Maybe pricing for a, say, 4 GHz scope (with probes!) will get
>>> reasonable some day.
>>>
>>>
>> You can get a TDS694 for $5k-ish.  3 GHz, 10 Gs/s.
>
> Thats way too expensive for such an old scope. I strongly doubt you
> can actually use this scope at 3GHz. It has BNC inputs (where most
> other equipment uses N or SMB for anything over 500MHz). There several
> offered on Ebay but they are not getting sold for 5k.
>


(a) You can buy four of them for the price of anything comparable new;
(b) They work great.
(c) Nobody spending his own money buys for what the dealers are asking.

I've got one on my shopping list for 2012--we'll see!

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
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
Reply by Fred Bartoli ●February 15, 20122012-02-15
John Larkin a &#4294967295;crit :

> On Mon, 13 Feb 2012 20:03:34 -0800, Robert Baer
> <robertbaer@localnet.com> wrote:
> 
>> Phil Hobbs wrote:
>>> On 02/13/2012 03:12 AM, Okkim Atnarivik wrote:
>>>> Phil Hobbs<pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>> : I started by taking your advice, which was pretty valuable--thanks
>>>>
>>>> Don't mention it. I have already gained more from your, Larkin's,
>>>> Win Hill's and many other's posts here in SED.
>>>>
>>>> : again. I noticed the change in specs as well, when I ordered another
>>>> : batch a couple of months ago. They changed the type number to BFP650H
>>>> : instead of BFP650E when they changed the process. (The dogs.)
>>>>
>>>> They did? The datasheet still list the part as BFP650 without suffixes
>>>> even though it is the SiGe:C version.
>>> The distributors' stock of the E version all ran out a few months ago,
>>> and all they have now is the H version. I haven't managed to get the
>>> straight story as to just what they did.
>>>
>>>> : I'm using it as a cascode stage for a SKY65050 pHEMT, and it works
>>>>
>>>> Interesting hint, I should give it a try.
>>>>
>>>> : great. One of the best things about it is that it has effectively
>>>> : infinite Early voltage, so you can get a lot of voltage gain out of a
>>>> : single stage. Even for situations where you don't care so much about
>>>> : ultralow noise, the combination of a gigantic f_T with a very high V_A
>>>> : is unique in my collection. It does want to oscillate at 14 GHz if you
>>>> : look at it crosswise, but a nice 5-ohm bead in series with the base
>>>> : cleans that right up.
>>>>
>>>> The high Early seems to be characteristic to the SiGe's, it puzzled me
>>>> already in the thread http://tinyurl.com/8a44pzn . If you check the
>>>> page 4 of http://tinyurl.com/6qmnd4u you see it there too (and
>>>> additionally
>>>> you get the large hFE = 400 ).
>>> I've ordered some of those too, thanks. It's a bit worrying that there
>>> are seem to be only about 100 of them in the world, according to FindChips.
>>>
>>> Cheers
>>>
>>> Phil
>>>> Regards,
>>>> Mikko
>>>
>>   Oh..i like that non-functional circuit on page two..
> 
> Wow, that's pretty bad.
> 


And the comments above the wonderful circuit is pretty bad as well...




> Are they suggesting that, since it's beta bracketed, it should be beta
> biased? Certain parties Would Not Approve. Makes sense for RF amps.
> 
> 



-- 
Thanks,
Fred.
Reply by Nico Coesel ●February 15, 20122012-02-15
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:


>On 02/14/2012 04:41 PM, John Larkin wrote:
>> On Tue, 14 Feb 2012 18:46:18 +0100, Gerhard Hoffmann<dk4xp@arcor.de>
>> wrote:
>>
>>> On 02/14/2012 04:16 PM, John Larkin wrote:
>>>> On Tue, 14 Feb 2012 08:56:40 +0100, Gerhard Hoffmann<dk4xp@arcor.de>
>>>> wrote:
>>>>
>>>>> On 02/14/2012 01:22 AM, BobW wrote:
>>>>>
>>>>>> We're looking at the latest LeCroy scopes to look at 37GHz signals.
>>>>>> Their new 10 series has up to 60GHz of bandwidth and 160GSamples/s (real
>>>>>> time). It's only about $400K :-|. They use 2.4mm connectors. I'm not
>>>>>> sure if you can get a direct MMPX<->2.4mm without adapters.
>>>>>
>>>>> In december, we had one of these 80 GSPS real time thingies from Agilent
>>>>> for a week to test, made me quite greedy.
>>>>>
>>>>> Gerhard
>>>>
>>>> I have a Tek 11801 sampler with a 40 GHz head. Costs about $2K on
>>>> ebay.
>>>
>>>
>>> That was at my customer's.
>>>
>>> I myself have a hp54750a with 20 and 50 GHz plug-ins, 9 ps risetime.
>>> But it is not real-time. One cannot trigger on the one bit error in
>>> a 10 GB/s fiber optic link that may or may not happen this night.
>>>
>>> 5 years ago, we could have been faster by 6 weeks during the
>>> development of a XFP transceiver.
>>
>> A realtime scope would be handy around here for snooping PCI Express
>> signals. Maybe pricing for a, say, 4 GHz scope (with probes!) will get
>> reasonable some day.
>>
>>
>You can get a TDS694 for $5k-ish.  3 GHz, 10 Gs/s.


Thats way too expensive for such an old scope. I strongly doubt you
can actually use this scope at 3GHz. It has BNC inputs (where most
other equipment uses N or SMB for anything over 500MHz). There several
offered on Ebay but they are not getting sold for 5k.

-- 
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------
Reply by John Larkin ●February 15, 20122012-02-15
On Wed, 15 Feb 2012 06:13:08 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:


>On Feb 14, 9:08&#4294967295;pm, Bill Sloman <bill.slo...@ieee.org> wrote:
>> On Feb 15, 2:36&#4294967295;am, George Herold <gher...@teachspin.com> wrote:
>>
>>
>>
>>
>>
>> > On Feb 14, 5:56&#4294967295;pm, Gerhard Hoffmann <dk...@arcor.de> wrote:
>>
>> > > On 02/14/2012 02:34 PM, Phil Hobbs wrote:
>>
>> > > > Gerhard Hoffmann wrote:
>> > > >> Yesterday, I changed a Wilson current mirror from BFT93 to
>> > > >> Intersil HFA3096. Used to work nicely with BFT93, but oscillates
>> > > >> like hell with the HFA3096 if it gets more than 1 mA &#4294967295; :-((
>>
>> > > >> I wonder what will happen with these extra-wide-body hermetic
>> > > >> flatpacks in place of the SO-16s. Probably nothing good.
>> > > >> But at least there is a rad-hardened version.
>>
>> > > >> Is there a sure way to calm down a Wilson current mirror without
>> > > >> too much sandbagging or introducing noise? It MUST work into
>> > > >> a capacitive load.
>> > > >> A simple mirror seems to be stable.
>>
>> > > No, the simple npn mirror wasn't stable, too :-(
>>
>> > > > Put a 10-100 ohm ferrite bead in series with each of the bases.
>> > > > (including the diode-connected ones).
>>
>> > > That's what I meant with sandbagging & noise. 50R makes it stable,
>> > > but it adds to Rbb. I won't get ferrites for fear of noise pickup.
>> > > As usual, no silver bullet. But many thanks, anyway.
>> > > And I like your book!
>>
>> > > sigh, Gerhard
>>
>> > Ouh, ferrites can add to magnetic pickup. &#4294967295;I never thought of that.
>>
>> Probably because it doesn't happen. A chunk of ferrite - aka a ferrite
>> bead - can provide a low permeability short-cut for any magnetic field
>> in the immediate vicinity, but ferrite beads are small and don't have
>> much of an immediate vicinity. The flux concentrations they produce
>> are going to be really hard to detect.
>
>After posting I realized that a ferrite 'bead' is just like a one turn
>toroid.  So it is pretty hard to couple in any field.
>It might be fun to try and measure.  A one loop 'pick-up' coil versus
>a coil with a ferrite bead on it.



Loops in the PCB trace layout will be better magnetic pickups than a
ferrite bead.


-- 

John Larkin, President       Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
Reply by George Herold ●February 15, 20122012-02-15
On Feb 14, 9:08=A0pm, Bill Sloman <bill.slo...@ieee.org> wrote:

> On Feb 15, 2:36=A0am, George Herold <gher...@teachspin.com> wrote:
>
>
>
>
>
> > On Feb 14, 5:56=A0pm, Gerhard Hoffmann <dk...@arcor.de> wrote:
>
> > > On 02/14/2012 02:34 PM, Phil Hobbs wrote:
>
> > > > Gerhard Hoffmann wrote:
> > > >> Yesterday, I changed a Wilson current mirror from BFT93 to
> > > >> Intersil HFA3096. Used to work nicely with BFT93, but oscillates
> > > >> like hell with the HFA3096 if it gets more than 1 mA =A0 :-((
>
> > > >> I wonder what will happen with these extra-wide-body hermetic
> > > >> flatpacks in place of the SO-16s. Probably nothing good.
> > > >> But at least there is a rad-hardened version.
>
> > > >> Is there a sure way to calm down a Wilson current mirror without
> > > >> too much sandbagging or introducing noise? It MUST work into
> > > >> a capacitive load.
> > > >> A simple mirror seems to be stable.
>
> > > No, the simple npn mirror wasn't stable, too :-(
>
> > > > Put a 10-100 ohm ferrite bead in series with each of the bases.
> > > > (including the diode-connected ones).
>
> > > That's what I meant with sandbagging & noise. 50R makes it stable,
> > > but it adds to Rbb. I won't get ferrites for fear of noise pickup.
> > > As usual, no silver bullet. But many thanks, anyway.
> > > And I like your book!
>
> > > sigh, Gerhard
>
> > Ouh, ferrites can add to magnetic pickup. =A0I never thought of that.
>
> Probably because it doesn't happen. A chunk of ferrite - aka a ferrite
> bead - can provide a low permeability short-cut for any magnetic field
> in the immediate vicinity, but ferrite beads are small and don't have
> much of an immediate vicinity. The flux concentrations they produce
> are going to be really hard to detect.


After posting I realized that a ferrite 'bead' is just like a one turn
toroid.  So it is pretty hard to couple in any field.
It might be fun to try and measure.  A one loop 'pick-up' coil versus
a coil with a ferrite bead on it.

George H.

>
> --
> Bill Sloman, Nijmegen- Hide quoted text -
>
> - Show quoted text -
Reply by Bill Sloman ●February 14, 20122012-02-14
On Feb 15, 2:36=A0am, George Herold <gher...@teachspin.com> wrote:

> On Feb 14, 5:56=A0pm, Gerhard Hoffmann <dk...@arcor.de> wrote:
>
>
>
>
>
>
>
>
>
> > On 02/14/2012 02:34 PM, Phil Hobbs wrote:
>
> > > Gerhard Hoffmann wrote:
> > >> Yesterday, I changed a Wilson current mirror from BFT93 to
> > >> Intersil HFA3096. Used to work nicely with BFT93, but oscillates
> > >> like hell with the HFA3096 if it gets more than 1 mA =A0 :-((
>
> > >> I wonder what will happen with these extra-wide-body hermetic
> > >> flatpacks in place of the SO-16s. Probably nothing good.
> > >> But at least there is a rad-hardened version.
>
> > >> Is there a sure way to calm down a Wilson current mirror without
> > >> too much sandbagging or introducing noise? It MUST work into
> > >> a capacitive load.
> > >> A simple mirror seems to be stable.
>
> > No, the simple npn mirror wasn't stable, too :-(
>
> > > Put a 10-100 ohm ferrite bead in series with each of the bases.
> > > (including the diode-connected ones).
>
> > That's what I meant with sandbagging & noise. 50R makes it stable,
> > but it adds to Rbb. I won't get ferrites for fear of noise pickup.
> > As usual, no silver bullet. But many thanks, anyway.
> > And I like your book!
>
> > sigh, Gerhard
>
> Ouh, ferrites can add to magnetic pickup. =A0I never thought of that.


Probably because it doesn't happen. A chunk of ferrite - aka a ferrite
bead - can provide a low permeability short-cut for any magnetic field
in the immediate vicinity, but ferrite beads are small and don't have
much of an immediate vicinity. The flux concentrations they produce
are going to be really hard to detect.

--
Bill Sloman, Nijmegen