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On Fri, 16 Feb 2007 14:18:55 -0500, CBFalconer <cbfalconer@yahoo.com> Gave us: > >All it takes is an infinite capacity capacitor. The turn-on time >and inrush current may be high. However it avoids the need for a >UPS. Once they get the breakdown voltage up and get them into >production we can have all the electric cars we want, and dispense >with all batteries. You ain't real bright. You must have been daydreaming about perpetual motion when the instructor covered this subject.Article: 115701
On Fri, 16 Feb 2007 20:03:52 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >Zero ripple is a real thing. Bullshit. The last supply I designed with our engineering group was for a CAT scanner, and it was EXACTLY 1500 volts, regulated to within one volt, and it had 2mV of ripple. That was AT the switching frequency of 17kHz at the full 250 Watts output. That took a half year and two iterations to achieve. We also made an xray supply that made 4kV at 1.5uA, and that had only 2mV of ripple at rated loading. Linear OR switcher, under full rated load, there IS going to be ripple voltages present. Period. You cannot look at a supply with no load on it, and declare it to be ripple free. You are compiling errant data if you do. Try again, Vlad.Article: 115702
Jon Elson wrote: > Tim wrote: <snip> >> If you think I'm exaggerating, try the Avnet site: >> >> Virtex-5 parts: all out of stock, no pricing >> Virtex-4 parts: out of 243 parts (mostly priced!) just 59 are available >> Spartan-3A parts: "Part is not found as a stocked item" >> Spartan-3E parts: prototype parts only and no higher volume pricing >> > This is a really disturbing trend. For a while I thought this was a > temporary disturbance > due to the RoHS debacle, but I think it is far more serious than that. I > think the entire > electronic industry in the US is in a death spiral. It has certainly cause a step effect, that has moved more stuff on this side to MOQ/Mfg leadtimes. > There are just a > RAFT of parts that I > can no longer get, that were stocked by several distributors just a year > ago. (TI, and > others, may be partially responsible for this by producing literally > DOZENS of variants > on ordinary parts. Some of the old CMOS 74HC parts are now available in > 5, 6 even > 7 different packages, 3 temp ranges, and dozens of varying electrical > and speed ranges. > So, a 74HC04 now expands to fill half a page of type that requires a > microscope to > read in the digi-key catalog. <snip> Logic has suffered from some false starts. Poor product management meant for a while, some vendors thought 5V was going to die - It took a while, but now most devices spec 1.65-5.5V logic capability, and hot-plug is a common new feature too. There is no real excuse for temperature variants on logic (or SPLD/CPLD) these days, and most Logic devices (eg Philips/NXP) are SINGLE part numbers/devices, with TWO sets of data columns. One for 85'C and one for 125'C. They do not bother with two speed grades - it's not like they have signifcant yield issues these days! That makes strong sense, as it simplifies the production and stocking, and speeds design wins. Not all vendors are as up-to-date in their thinking, and some still see an industrial temp device, as license for more margin. Since this started as a Xilinx thread, if we look at their OnLine "store",[CoolRunnerII example] they show ONLY commercial grade devices ?! - where does that leave industrial customers ? Are Xilinx yields really so variable, that they need 3 part numbers for each package-die variant ? - much more sensible to rationalise that down to 1, and greatly imrove the chances a designer will find it in stock!. -jgArticle: 115703
> >>> Indeed there are the topologies of the switchers with exactly >>> zero or almost zero ripple, assuming the ideal symmetry of >>> everything. >> Like a polyphase switcher with *big* inductors? But I don't want >> "almost zero ripple", I want the real thing. > Zero ripple is a real thing. Imagine the two identical bucks > operating 50/50 duty with 180 degree phase shift on the common load. > Ideally, there will be no ripple at the load at all. There are > numerous patents on the variations of this idea, allowing to adjust > the duty, different topologies and such. MassiveProng wrote: > Bullshit. I don't beleive you didn't understand what is the previous quoting about. > > The last supply I designed with our engineering group was for a CAT > scanner, and it was EXACTLY 1500 volts, regulated to within one volt, > and it had 2mV of ripple. It could be done better then that. > That was AT the switching frequency of > 17kHz at the full 250 Watts output. > That took a half year and two iterations to achieve. Good for you. Although very slow. > We also made an xray supply that made 4kV at 1.5uA, and that had only > 2mV of ripple at rated loading. 1.5uA is not much. > Linear OR switcher, under full rated load, there IS going to be > ripple voltages present. Period. You don't have to preach that 2 + 2 = 4. > You cannot look at a supply with no load on it, and declare it to be > ripple free. You are compiling errant data if you do. > Try again, Vlad. I don't care. It is not my problem. VLVArticle: 115704
On Sat, 17 Feb 2007 01:22:51 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >It could be done better then that. Not in the package constraints we had. We bettered the competitor's product as well. They were unable to achieve the spec. Do you even know what that ripple figure represents? That's 0.000001333 % ripple. You won't be getting lower than that any time soon in the chassis we did it in at 250 Watts loading. I don't think you are aware of what is or is not "being done". You're just spittin' out words to see where they splatter.Article: 115705
On Sat, 17 Feb 2007 01:22:51 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >Good for you. Although very slow. Nope. It was dual audio amps feeding a center tapped transformer and multiplier stage. We found the right frequency for the application with the hardware topology we used.Article: 115706
On Sat, 17 Feb 2007 01:22:51 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >> We also made an xray supply that made 4kV at 1.5uA, and that had only >> 2mV of ripple at rated loading. > >1.5uA is not much. You don't know much about X-ray flux, or the generation thereof.Article: 115707
On Sat, 17 Feb 2007 01:22:51 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >> Linear OR switcher, under full rated load, there IS going to be >> ripple voltages present. Period. > >You don't have to preach that 2 + 2 = 4. Aren't you the dolt that claimed that zero ripple supplies are easy to make?Article: 115708
On Sat, 17 Feb 2007 01:22:51 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >I don't care. It is not my problem. Why are you even in the fucking thread then, dipshit?Article: 115709
MassiveProng wrote: >>It could be done better then that. > > Not in the package constraints we had. We bettered the competitor's > product as well. They were unable to achieve the spec. > > Do you even know what that ripple figure represents? Yes, I do know that very well, since I do work on the audio and measurement equipment. > That's 0.000001333 % ripple. This is -117dB. No doubts it is a decent result, although it is not a world record by any means. > You won't be getting lower than that any time soon in the chassis we > did it in at 250 Watts loading. > I don't think you are aware of what is or is not "being done". > You're just spittin' out words to see where they splatter. I can't understand. Are you trying to scare a porcupine by showing him a naked butt? VLVArticle: 115710
MassiveProng wrote: >>Linear OR switcher, under full rated load, there IS going to be >>>ripple voltages present. Period. >> >>You don't have to preach that 2 + 2 = 4. > > > > Aren't you the dolt that claimed that zero ripple supplies are easy > to make? Dude, do you read the words which I didn't wrote? Please find a quote or go take your pills. VLVArticle: 115711
MassiveProng wrote: > On Sat, 17 Feb 2007 01:22:51 GMT, Vladimir Vassilevsky > <antispam_bogus@hotmail.com> Gave us: > > >>I don't care. It is not my problem. > > > Why are you even in the fucking thread then, dipshit? And this is not your problem. VLVArticle: 115712
MassiveProng wrote: >>>We also made an xray supply that made 4kV at 1.5uA, and that had only >>>2mV of ripple at rated loading. >> >>1.5uA is not much. > > You don't know much about X-ray flux, or the generation thereof. Sorry, dude. At one time I was working with the X-ray crystallograph. The tube was typically operating at 40...50kV, draining the current about 10..15mA. So here we go. VLVArticle: 115713
On Sat, 17 Feb 2007 02:07:45 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >This is -117dB. No doubts it is a decent result, although it is not a >world record by any means. For a power supply? You're nuts. ESPECIALLY at 1500 volts.Article: 115714
On Sat, 17 Feb 2007 02:15:40 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: > > >MassiveProng wrote: > >> On Sat, 17 Feb 2007 01:22:51 GMT, Vladimir Vassilevsky >> <antispam_bogus@hotmail.com> Gave us: >> >> >>>I don't care. It is not my problem. >> >> >> Why are you even in the fucking thread then, dipshit? > >And this is not your problem. > >VLV And you can fuck off.Article: 115715
On Sat, 17 Feb 2007 02:10:34 GMT, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: >Please find a quote or go take your pills. I got a pill for your ass, fuckhead.Article: 115716
On Fri, 16 Feb 2007 20:21:34 -0600, Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us: > > >MassiveProng wrote: > >>>>We also made an xray supply that made 4kV at 1.5uA, and that had only >>>>2mV of ripple at rated loading. >>> >>>1.5uA is not much. >> >> You don't know much about X-ray flux, or the generation thereof. > >Sorry, dude. At one time I was working with the X-ray crystallograph. >The tube was typically operating at 40...50kV, draining the current >about 10..15mA. So here we go. And THAT supply ALSO had a pretty low ripple figure, I'll guarantee you. The whole idea behind clean DC for the X-ray tube is that the X-ray flux is clean and pure. THAT yields the best contrast ratio in the imagery. The supply I mentioned feeds a small device meant for looking at gas pipes in city streets. I also made a supply that was 50kV at 250Watts That's only 5mA. So your supplies were leaning toward a kW, eh? That must have been some X-ray flux. Still, you should have known that the ripple figure I gave for the CAT supply was exceedingly low. By ALL standards.Article: 115717
> And funny enough, Avnet gave us a first price estimation for quantity 1000 of an > 1600E higher than the prototype price in their webshop. I don't know what they > are smoking... Don't blame Avnet, all pricing comes from Xilinx or the local rep. The reality is that _if_ Xilinx thinks your product/project is worthwhile you get samples, small quantities for pilot production runs, and a good price for volume. If they don't, then you get to twist in the wind. To be fair, this is a pretty common industry wide practice and Xilinx has always done very well by me. Since Peter and Austin want to self-promote (or guerilla market) their way to Innovative Product of Year I suggest they put their money where their mouths are and put any Virtex-5 part up on the web store for a little less than the usual tourist pricing. After all, we've all heard how they've got _so_ many extra in stock they are looking to unload. If they do that, they've bought my vote. So what about it Peter and Austin, man or mouse? Ricky.Article: 115718
MassiveProng wrote: > > On Fri, 16 Feb 2007 18:17:02 GMT, "Michael A. Terrell" > <mike.terrell@earthlink.net> Gave us: > > >John Larkin wrote: > >> > >> Please post the schematic of a zero-ripple switcher. > >> > >> John > > > > > > Sorry, but that feature is only available on the 0 volt model. > > Are they fooly regulated? As regulated as a dead short can be. ;-) -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central FloridaArticle: 115719
MassiveProng wrote:
> Vladimir Vassilevsky <antispam_bogus@hotmail.com> Gave us:
>
>> Please find a quote or go take your pills.
>
> I got a pill for your ass, fuckhead.
This sort of foolish language will sooner or later get you PLONKed
--
<http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.txt>
<http://www.securityfocus.com/columnists/423>
"A man who is right every time is not likely to do very much."
-- Francis Crick, co-discover of DNA
"There is nothing more amazing than stupidity in action."
-- Thomas Matthews
Article: 115720On Fri, 16 Feb 2007 19:52:36 -0800, MassiveProng <MassiveProng@thebarattheendoftheuniverse.org> wrote: >On Sat, 17 Feb 2007 02:10:34 GMT, Vladimir Vassilevsky ><antispam_bogus@hotmail.com> Gave us: > >>Please find a quote or go take your pills. > > I got a pill for your ass, fuckhead. Still got that anal/fecal thing going, I see. I'm sure glad I wasn't born with a fetish like that. JohnArticle: 115721
ricky, Peter and I take this issue of pricing and availability quite seriously. We have begun discussions on the issue. If you think you are upset by this, try to place yourselves in the shoes of the hundreds of hardware ICDES folks, and hundreds of software folks, and hundreds of production test and characterization engineers...you get the picture. I went to some of the other nominee's websites, and on one, I could: order a sample, order parts, have a representative contact me (the buttons I could click on). 10K pricing was listed. I think there is significant room for improvement here. AustinArticle: 115722
I am trying to perform a simple behavioral simulation of a baud rate clock generation module. The module is straightforward and will synthesize properly, so I am fairly confident that it is written correctly. However, just to verify, I want to simulate it. I create a test bench waveform file and set up the clock @ the correct frequency, set all of the inputs properly, and save the file. When I run the simulation, I have the following problems: 1) All of the inputs which were set and saved now appear as high impedance 2) Additional output signals which were not present in the test becnch waveform now appear such as PERIOD[31:0] 3) All of my outputs of interest appear as X (unknown) Any thoughts / suggestions? Thanks, ScottArticle: 115723
"ScottNortman" <scott.nortman@gmail.com> wrote in message news:1171730229.882232.255480@t69g2000cwt.googlegroups.com... >I am trying to perform a simple behavioral simulation of a baud rate > clock generation module. The module is straightforward and will > synthesize properly, so I am fairly confident that it is written > correctly. However, just to verify, I want to simulate it. That's a somewhat backwards approach. First you need to get the behaviour correct in simulation and THEN synthesize it. Correct behaviour in simulation is what gives you confidence that what you've written will implement whatever function it is that you want to do. Getting through synthesis simply says that what you've written (whether it is functionally correct or not) can be implemented. Ultimately both are important, but most experienced designers concentrate on getting function correct (as verified by the simulator) and then (or as a background task while simulating) run through synthesis to make sure that when they really are ready to synthesize there won't be any surprises. > > I create a test bench waveform file and set up the clock @ the correct > frequency, set all of the inputs properly, and save the file. > > When I run the simulation, I have the following problems: > > 1) All of the inputs which were set and saved now appear as high > impedance Sounds like one of the following: - The 'inputs' are actually I/O pins - Or this is a post route simulation and you're not actually forcing the inputs to anything and the post-route simulation model drives them to a high impedance state. - Or, if this is a post route simulation than however it is you're forcing your inputs you're not overriding the 'Z' drive of the post route simulation. Check to see how you're forcing these inputs, look for something like a 'freeze' option, which says that the 'force' statements override anything else. Basically double check how it is you're providing stimulus to your design, it doesn't look like you're doing it correctly. > 2) Additional output signals which were not present in the test > becnch waveform now appear such as PERIOD[31:0] Sounds like you're not simulating the top level of your design then....presumably PERIOD[31:0] is some internal signal that is not supposed to be at the top level of the design....so figure out exactly what entity you're simulating. > 3) All of my outputs of interest appear as X (unknown) Most likely because your inputs are not being forced correctly (see above). Kevin JenningsArticle: 115724
On Fri, 16 Feb 2007 10:14:41 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>On Fri, 16 Feb 2007 18:58:54 +0100, "Geronimo Stempovski"
><geronimo.stempovski@arcor.de> wrote:
>
>>
>>"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> schrieb im
>>Newsbeitrag >
>>> No, what are you trying to *do*? WHY do you want a "coax on a pc
>>> board"?
>>>
>>
>>Ah, okay, what I am actually trying to find out is what makes FR4 act worse
>>than e.g. teflon at data rates beyond 2,5 Gbps. Is it the loss tangent or
>>the epsilon r? How is the frequency-dependent attenuation physically
>>describable? Where does the energy go? Heat, ...? It was my opinion that
>>higher frequencies can be transmitted over coax but not over FR4 because of
>>the geometry. Because in a coax there is (almost) no energy loss because the
>>TEM wave is "captured" by the outer shield and in a planar setup like
>>stripline or microstrip there are E-field and H-field lines vanish into the
>>air environment (or somewhere else...). Therefore I'm trying to design a
>>coax on a PCB. Am I right with my thoughts, anyway?
>>
>
>A couple of things make pcb's lossy: the loss tangent of the material
>(and FR4 is pretty bad) and the copper losses. Copper loss gets bad on
>conventional FR4 boards because
>
>1. FR4's Er is high, so for a given impedance traces are skinny.
>
>2. The underside of the copper is treated to bond to the epoxy/glass,
>and the treatment (black oxide or something) greatly increases skin
>losses. Peel some up and look... it's gross.
>
>3. In the case of microstrip, the current is concentrated on the
>underside (the dirty side) of the trace, so losses are that much
>worse... the shiny topside of the copper is underutilized. Stripline
>would be better, with balanced current density, except that the trace
>will be much thinner, which has its own penalty.
>
>
>A good microwave pcb has a low Er, low loss dielectric; is thick, for
>low current density and wide traces; has very smooth copper, which
>means traces and pads peel off easily.
>
>I don't think any simple geometry tricks (ie, emulating coax) will
>make FR4 any better, and would probably make it worse. For low losses,
>microstrip on a thick board is probably as good as it gets.
>
>John
>
>
Suppose you did an FR4 pcb with a wide microstrip on the top, then
route out most of the material below the trace, namely route a trench
under the trace, from the opposite side, say 90% of the board
thickness. Now we'd have a sort of suspended substrate trace, much
wider for a given Z, with much lower losses. We could call it
LarkinLine.
-------------- copper trace
=================================================
================== ================= epoxy-glass
================== air =================
------------------ ----------------- copper gnd
I haven't a clue how to calculate the impedance; field solver, like
ATLC maybe?
John
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