On Wed, 16 Oct 2013 23:38:24 -0700, miso <miso@sushi.com> wrote:>On 10/16/2013 10:21 PM, John Larkin wrote: >> On Wed, 16 Oct 2013 19:58:40 -0700, miso <miso@sushi.com> wrote: >> >>> On 10/16/2013 12:37 PM, John Larkin wrote: >>>> On Wed, 16 Oct 2013 14:29:29 -0500, John S <Sophi.2@invalid.org> >>>> wrote: >>>> >>>>> On 10/16/2013 12:40 PM, Tom Del Rosso wrote: >>>>>> John Larkin wrote: >>>>>>> the technical guy said that this is a single-supply opamp and might not be >>>>>>> qualified for dual-supply >>>>>>> operation. >>>>>> >>>>>> I don't have a degree and I'm hardly the most competent hobbyist, but maybe >>>>>> I could work there. >>>>>> >>>>>> >>>>> >>>>> Perhaps you should written "I don't have a degree and I'm hardly the >>>>> most competent hobbyist, so I'm sure I could work there." >>>>> >>>>> We should go apply. >>>> >>>> "Not getting back to potential customers" is another required skill. >>>> >>>> >>> >>> Then again, maybe Maxim apps reads SED and knows who they are dealing with. >> >> I especially enjoyed the Maxim engineer's "not characterized for dual supply >> operation" comment. I now know who *I* am dealing with. >> >> Last time I used Maxim parts, we had to recall hundreds of timing modules and >> replace about 3000 pieces of MAX9690 comparators. They started failing after >> roughly a year of use, and eventually every one would have failed. The parts >> were actually fabbed (and maybe designed?) by a subcontractor, in Minnesota I >> heard. >> >> We had to make 3000 of these to replace them: >> >> https://dl.dropboxusercontent.com/u/53724080/Circuits/Break2.jpg >> >> https://dl.dropboxusercontent.com/u/53724080/Circuits/OnBoard.jpg >> >> It was rather an expensive nuisance. >> >> >> > >And what did FA say? Well assuming you contacted them. It is quite easy >to find damage to chips given tools like emission microscopes. Generally >failed parts are due to the customer, and you can get some good >diagnostics by asking the factory how the part failed.The outputs got erratic at high temperature, looked like a problem in the latch circuit. As the parts aged, the fail temperature descended, ultimately reaching room temp after about a year. All the parts did this. A good hi-temp bake would push the fail temperature up, and it would begin slowly descending again from there. What would cause that? Our first indication that something was wrong was when parts wouldn't ship, with no explanation. Then the part was discontinued, delivery infinite days ARO, again without explanation. That was about the time they started failing. I eventually found a guy at Maxim who explained the Minnesota problem. He sent me 3000 samples of the MAX9691. The 9691 is a *comparator* with back-to-back diodes across the inputs (!!!!???) which is why we had to make the adapter boards. -- John Larkin 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
Never Buy Maxim (again)
Started by ●October 13, 2013
Reply by ●October 17, 20132013-10-17
Reply by ●October 17, 20132013-10-17
On Wed, 16 Oct 2013 23:38:24 -0700, miso <miso@sushi.com> wrote: [snip]>> > >And what did FA say? Well assuming you contacted them. It is quite easy >to find damage to chips given tools like emission microscopes. Generally >failed parts are due to the customer, and you can get some good >diagnostics by asking the factory how the part failed. > >I had Moto bitching about one of my parts. They used 4 per board. Only >one position on the board would have a failed part. Moto felt a bit >stupid not noticing that and simply went away, presumably finding the >problem since they kept buying the parts long after the incident. Pilot >error. It is nearly always pilot error. > >Designing ESD devices for interface chips, I spent some time in the FA >lab destroying parts to understand what exactly fails. Emission >microscopy detects stressed junctions, but some failures cause the >juction to do ohmic. You can find those with a simple CCD, but liquid >crystals is a better technique. The crystals will "boil" over the hot >spot. You can pulse the chip to make the hot spot toggle, or my >technique was to just leave it powered and bring a soldering iron close >to the chip. The iron would get the crystals just ready to change state, >making it a very sensitive technique. > >Minnesota parts were from VTC. To my knowledge, they didn't have any >designers, just a fab.That would be correct. Quite a nice fab. Excellent BiCMOS processes. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●October 17, 20132013-10-17
BS > Jim-out-of-touch-with-reality-Thompson strikes again. BS > John Larkin exhibits a much broader spectrum of BS > ignorance than krw, and has been known to post BS > circuit diagrams and LTSpice net-lists. BS > BS > We may be arguing precedence between a flea BS > and a louse, but Larkin is definitely the BS > performing flea and krw the crawling louse. G > Has your wife been catching on to you, slow man? BS > I wonder what that was intended to mean? G > It was open ended. BS > Which is to say more of Greegor's contentless drivel. Flatterer. G > Your rundown seems like a catharsis for you. BS > My mother just died, and my kidney stone BS > has been lithotripted into a very small BS > pieces, which also seemed to turn off BS > my right kidney for three days. BS > BS > Losing a parent - or what was left BS > of her at 95 - probably qualifies BS > as catharsis, but I don't need BS > purification or cleansing to find BS > an excuse to be rude about krw who BS > must rate as the most despicable BS > non-contributor to this usegroup. BS > BS > He doesn't like me much either. G > Slow Man: When avowed socialists from G > other countries start manipulating G > information to try to sell Socialism G > to people in the USA, we don't like it. BS > It's strictly for your own good. Socialists and Stateists say that a lot! BS > The shameless information manipulation BS > that lead you to believe that socialism BS > and communism are the same thing needs BS > to be shown up. I compared you to another avowed SOCIALIST, not a communist and what was your reaction? BS > <snipped irrelevant stuff about someone who posts elsewhere> I'm starting to think you are more dishonest than I thought. G > I know that Jim Thompson thinks that G > this usenet group is dominated by G > left wing posters, but it's not as G > left wing dominated as the rest of G > usenet is. G > G > My personal belief BS > <snipped more irrelevant prejudice> Just put your fingers in your ears and make childish noises, Slow man. BS > This thread started off on the defects of BS > Maxim. A little bit of off-topic deviation BS > is tolerable, but you are away with the BS > fairies - of the old-fashioned asexual kind. You ad-hommed 3 regular posters all at once. Typical of Socialists and Aspies you frequently put on aires of superiority, disrespect others and present YOUR prejudices as enlightenment. When I pointed out that you are an avowed Socialist, you tried danced around that fact, comparing different political parties in Australia, none of which had any bearing on the simple fact that you are an outright Socialist. Why do you try so hard to weasel out of that?
Reply by ●October 17, 20132013-10-17
On Wed, 16 Oct 2013 19:54:29 -0700, miso <miso@sushi.com> wrote:>On 10/15/2013 7:09 AM, John Larkin wrote: >> On Mon, 14 Oct 2013 21:53:29 -0700, miso <miso@sushi.com> wrote: >> >>> On 10/14/2013 2:51 PM, John Larkin wrote: >>>> On Mon, 14 Oct 2013 17:20:03 -0400, "tm" <No_one_home@white-house.gov> >>>> wrote: >>>> >>>>> >>>>> "miso" <miso@sushi.com> wrote in message >>>>> news:l3hi8e$ql7$1@speranza.aioe.org... >>>>>> On 10/13/2013 12:34 PM, John Larkin wrote: >>>>>>> >>>>>>> These opamps, like most Maxim parts, have nonstandard pinout. I built a >>>>>>> test >>>>>>> fixture to measure Cin. With power off, I measured 1.4 pF on the >>>>>>> non-inverting >>>>>>> input pin. >>>>>> Who measures capacitance of a part that is powered down? Doh! There are >>>>>> diodes that need to be reverse biased ya know. >>>>>> >>>>>> Do you have someone who works for you that is, well you know, a competent >>>>>> electrical engineer? Perhaps you are not suited for electrical >>>>>> engineering. Have you considered software? >>>>>> >>>>>> >>>>>> >>>>> >>>>> It's called "characterizing the part". It is way beyond a libtard such as >>>>> yourself to understand. >>>>> >>>> >>>> I'm curious about things like ESD capacitance. Given a test setup, why >>>> would anyone *not* want to measure the power-off capacitance, and then >>>> determine the C-V behavior? >>>> >>>> >>> >>> ESD capacitance? We are now making up specifications? >> >> Don't be tedious. ESD capacitance is the capacitance of the ESD diodes. What >> else would I be measuring? > >Unless you have a test structure, you are not measuring the capacitance >of the ESD diodes, but rather whatever is on that pin, which would >include the input device. [Most chips only use one diode these days >since there is a tendency for boards with mixed supply voltages. Diodes >to the positive rail can be a problem if the board designer is sloppy in >supply sequencing (which is usually the case). > >> >>> >>> The ESD structure is part of the pin capacitance. However, nobody >>> specifies the capacitance of the part that is not in a normal operating >>> state. >> >> So that is, apparently, something that you adamantly don't want to ever measure >> or know. Cover up that C-meter so you don't accidentally find out. >> >> > >I don't make useless measurements.I make all sorts of "useless" measurements. Some of them turn out to be very useful. You define yourself by the things that you are not interested in. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●October 17, 20132013-10-17
Slow man: In 5,000 words or less could you please explain why you think your fecal matter doesn't smell bad? No dissertation on your diet or semantic arguments about the relative meaning of the word "bad", please.
Reply by ●October 17, 20132013-10-17
JL > The outputs got erratic at high temperature, JL > looked like a problem in the latch circuit. JL > As the parts aged, the fail temperature JL > descended, ultimately reaching room temp JL > after about a year. All the parts did this. JL > A good hi-temp bake would push the fail JL > temperature up, and it would begin slowly JL > descending again from there. What would cause that? Hygroscopy - tending to absorb moisture from the air Did somebody get the wrong polymer for the chip packages? The porosity or permeability of plastics are counter intuitive. Jim Thompson: Please tell us what you would suggest could cause such odd symptoms. In the middle 80's there were reports of water droplets inside of DRAM chips causing intermittent failures. Was that likely the real issue?
Reply by ●October 17, 20132013-10-17
On Sunday, October 13, 2013 2:34:32 PM UTC-5, John Larkin wrote:> Maxim makes an opamp, MAX44280, that has a specified input capacitance of 0.4 > > pF. That would be great in some apps where Cin causes noise-gain peaking. > > > > I figured I'd give Maxim another chance, after being s*****d by them in the > > past. > > > > So I went online and filled out their sample request. The process makes no > > sense, website runaround, but eventually I got it done. > > > > Two days later I got an email to the effect that the sample request was waiting > > for a product-line manager approval. I responded and asked why, and was told > > that it was standard internal procedure and would take only another 24 hours. > > > > OK, a week later I got two samples, packaged in a short tube and wrapped in a > > ball of sticky masking tape. > > > > These opamps, like most Maxim parts, have nonstandard pinout. I built a test > > fixture to measure Cin. With power off, I measured 1.4 pF on the non-inverting > > input pin. I powered it up and the opamp didn't act anything like an opamp. I > > checked everything three times and figured the amp was blown, so I tried to > > replace it. It's an SC70, really tiny, and my tweezers slipped and I pogoed it > > into the carpet, never to be seen again. > > > > The sales engineer emailed me to see how the samples were coming along, and I > > told him the situation. He promised to get me 10 more ASAP. Then he called back > > with a technical guy. I explained my setup. I'm using +-2.5 volt supplies, and > > the technical guy said that this is a single-supply opamp and might not be > > qualified for dual-supply operation. He said he'd contact the designers or > > something. I asked him how they defined and measured the 0.4 pF Cin, and he said > > he'd find out. They were due to call me last Monday. > > > > So far, no more parts, no call. > > > > > > -- > > > > John Larkin 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 generatorsAhhh, this subject remind me one of the funny Max device... let say deviceX The spec saying that device X has an output pin to indicate its input signal presents or not (kind of LOST signal)... and somewhere the spec say it's an open collector We didn't care it's open drain or not, since we do not use that damn pin for any purpose.. just simple as we don't care like an X in logic, no micro controller on board, or anyone who cares about that LOST... So we let it float Guess what? we get the board built - and power it up, device X kept sleeping as it has been slept for age since its birth Anyone knows why it didn't wake up?
Reply by ●October 17, 20132013-10-17
On Thu, 17 Oct 2013 07:27:54 -0700, John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:> >The outputs got erratic at high temperature, looked like a problem in the latch >circuit. As the parts aged, the fail temperature descended, ultimately reaching >room temp after about a year. All the parts did this. A good hi-temp bake would >push the fail temperature up, and it would begin slowly descending again from >there. What would cause that?AFAIUI, MOSFETs slowly shift threshold a bit when you apply continous DC voltage to the gate. Something to do with trapped charges. Annealing at high temperature can reverse some of that. It was a big problem with CMOS-input op-amps used as precision comparators, but less of a problem with ideal op-amp circuits because the inputs would usually be balanced, so the shifts would cancel out.
Reply by ●October 17, 20132013-10-17
On Thu, 17 Oct 2013 12:18:27 -0700 (PDT), Greegor <greegor47@gmail.com> wrote:>JL > The outputs got erratic at high temperature, >JL > looked like a problem in the latch circuit. >JL > As the parts aged, the fail temperature >JL > descended, ultimately reaching room temp >JL > after about a year. All the parts did this. >JL > A good hi-temp bake would push the fail >JL > temperature up, and it would begin slowly >JL > descending again from there. What would cause that? > >Hygroscopy - tending to absorb moisture from the air > >Did somebody get the wrong polymer for the chip packages? > >The porosity or permeability of plastics are counter intuitive. > >Jim Thompson: Please tell us what you would >suggest could cause such odd symptoms. > >In the middle 80's there were reports >of water droplets inside of DRAM chips >causing intermittent failures. > >Was that likely the real issue?AFAIUI chips are normally passivated (there's effectively a layer of glass- actually SiOx/SiNx- on top of the chip with "holes" for the bonding pads. Conformal coating at the chip level. So, moisture is unlikely to be an issue in a low impedance circuit.
Reply by ●October 17, 20132013-10-17
On Thu, 17 Oct 2013 12:31:56 -0700 (PDT), ccon67@netscape.net wrote:>On Sunday, October 13, 2013 2:34:32 PM UTC-5, John Larkin wrote: >> Maxim makes an opamp, MAX44280, that has a specified input capacitance of 0.4 >> >> pF. That would be great in some apps where Cin causes noise-gain peaking. >> >> >> >> I figured I'd give Maxim another chance, after being s*****d by them in the >> >> past. >> >> >> >> So I went online and filled out their sample request. The process makes no >> >> sense, website runaround, but eventually I got it done. >> >> >> >> Two days later I got an email to the effect that the sample request was waiting >> >> for a product-line manager approval. I responded and asked why, and was told >> >> that it was standard internal procedure and would take only another 24 hours. >> >> >> >> OK, a week later I got two samples, packaged in a short tube and wrapped in a >> >> ball of sticky masking tape. >> >> >> >> These opamps, like most Maxim parts, have nonstandard pinout. I built a test >> >> fixture to measure Cin. With power off, I measured 1.4 pF on the non-inverting >> >> input pin. I powered it up and the opamp didn't act anything like an opamp. I >> >> checked everything three times and figured the amp was blown, so I tried to >> >> replace it. It's an SC70, really tiny, and my tweezers slipped and I pogoed it >> >> into the carpet, never to be seen again. >> >> >> >> The sales engineer emailed me to see how the samples were coming along, and I >> >> told him the situation. He promised to get me 10 more ASAP. Then he called back >> >> with a technical guy. I explained my setup. I'm using +-2.5 volt supplies, and >> >> the technical guy said that this is a single-supply opamp and might not be >> >> qualified for dual-supply operation. He said he'd contact the designers or >> >> something. I asked him how they defined and measured the 0.4 pF Cin, and he said >> >> he'd find out. They were due to call me last Monday. >> >> >> >> So far, no more parts, no call. >> >> >> >> >> >> -- >> >> >> >> John Larkin 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 > > >Ahhh, this subject remind me one of the funny Max device... let say deviceX > >The spec saying that device X has an output pin to indicate its input signal presents or not (kind of LOST signal)... and somewhere the spec say it's an open collector > >We didn't care it's open drain or not, since we do not use that damn pin for any purpose.. just simple as we don't care like an X in logic, no micro controller on board, or anyone who cares about that LOST... So we let it float > >Guess what? we get the board built - and power it up, device X kept sleeping as it has been slept for age since its birth > >Anyone knows why it didn't wake up?Because you let that "output" float? What was the p/n?
