Gerhard Hoffmann wrote:> > On 02/13/2012 04:21 PM, John Larkin wrote: > > On Mon, 13 Feb 2012 10:30:41 +0200 (EET), Okkim Atnarivik > > <Okkim.Atnarivik@twentyfour.fi.invalid> wrote: > > > >> John Larkin<jjlarkin@highnotlandthistechnologypart.com> wrote: > >> : But if I wanted a negative current source, I'd just cascode into a > >> : PHEMT. I need positive current, and the people who make gaasfets > >> : stubbornly refuse to make p-channel ones. > >> > >> The same with SiGe PNP's - I would have wanted to make a push-pull > >> for LHe but there are no discretes available. An NPN-NPN push-pull > >> is a possibility, but awkward. Maybe the discretes will become available > >> soon, at least there are complementary IC processes producing such > >> devices as the OPA835/6 (which actually work in LHe but only marginally). > >> > >> Regards, > >> Mikko > > > > Unfortunately, most of the good fast parts are designed for RF use, > > which means we only get n-types, and very badly characterized ones at > > that. S-params and load pulls don't tell you much about DC or > > switching behavior. You're lucky if they tell you Idss, very lucky if > > they give you DC curves, and heaven is getting a Spice model. > > > > It's even worse if you want a fast PNP that is space-proof. > Say, a BFT93 in a metal can. Nothing. If there was one, you can be > sure that its qualification has timed out 10 years ago... > > 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 :-(( > > 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. > > > I asked Mini-Circuits if one of their MMICs inverts the signal or not. > > They didn't know. > > > > I think they just relabel semiconductors they buy somewhere else, and > they may even switch manufacturers. I think that was the case for ERAs. > > And the phase noise of old SRA-1 used to be better than it is now. > But it was never specified, so we cannot complain. Still have NOS. > > > Grrrrr. > > > > Rrrrrrrrrright! > > GerhardPut a 10-100 ohm ferrite bead in series with each of the bases. (including the diode-connected ones). 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
picosecond test points
Started by ●February 11, 2012
Reply by ●February 14, 20122012-02-14
Reply by ●February 14, 20122012-02-14
On Tue, 14 Feb 2012 08:48:15 +0100, Gerhard Hoffmann <dk4xp@arcor.de> wrote:>On 02/13/2012 04:21 PM, John Larkin wrote: >> On Mon, 13 Feb 2012 10:30:41 +0200 (EET), Okkim Atnarivik >> <Okkim.Atnarivik@twentyfour.fi.invalid> wrote: >> >>> John Larkin<jjlarkin@highnotlandthistechnologypart.com> wrote: >>> : But if I wanted a negative current source, I'd just cascode into a >>> : PHEMT. I need positive current, and the people who make gaasfets >>> : stubbornly refuse to make p-channel ones. >>> >>> The same with SiGe PNP's - I would have wanted to make a push-pull >>> for LHe but there are no discretes available. An NPN-NPN push-pull >>> is a possibility, but awkward. Maybe the discretes will become available >>> soon, at least there are complementary IC processes producing such >>> devices as the OPA835/6 (which actually work in LHe but only marginally). >>> >>> Regards, >>> Mikko >> >> Unfortunately, most of the good fast parts are designed for RF use, >> which means we only get n-types, and very badly characterized ones at >> that. S-params and load pulls don't tell you much about DC or >> switching behavior. You're lucky if they tell you Idss, very lucky if >> they give you DC curves, and heaven is getting a Spice model. >> > >It's even worse if you want a fast PNP that is space-proof. >Say, a BFT93 in a metal can. Nothing. If there was one, you can be >sure that its qualification has timed out 10 years ago... > >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 :-(( > >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. > > >> I asked Mini-Circuits if one of their MMICs inverts the signal or not. >> They didn't know. >> > >I think they just relabel semiconductors they buy somewhere else, and >they may even switch manufacturers. I think that was the case for ERAs.Right. They trashed the ERA5 beyond recognition. Caused us grrrrrief.> >And the phase noise of old SRA-1 used to be better than it is now. >But it was never specified, so we cannot complain. Still have NOS. > >> Grrrrr. >> > >Rrrrrrrrrright! > >Gerhard-- 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 ●February 14, 20122012-02-14
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. > >GerhardI have a Tek 11801 sampler with a 40 GHz head. Costs about $2K on ebay. -- 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 ●February 14, 20122012-02-14
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.
Reply by ●February 14, 20122012-02-14
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. Are they suggesting that, since it's beta bracketed, it should be beta biased? Certain parties Would Not Approve. Makes sense for RF amps. -- 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 ●February 14, 20122012-02-14
On 02/14/2012 10:16 AM, 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. > >Plus it doesn't run Windows! 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 ●February 14, 20122012-02-14
On 02/14/2012 12:46 PM, Gerhard Hoffmann 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. >Well, you can trigger off it--delay lines are easy in fibre--but you only get one data point per trigger. Just choose that point well. ;) 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 ●February 14, 20122012-02-14
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. -- 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 ●February 14, 20122012-02-14
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. 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 ●February 14, 20122012-02-14
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 :-(( >> >> 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
