Fast, efficient IR LEDs?
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From: miso on 5 Feb 2010 22:48 On Feb 5, 2:20 pm, Joerg <inva...(a)invalid.invalid> wrote: > Phil Hobbs wrote: > > On 2/5/2010 2:13 PM, m...(a)sushi.com wrote: > >> On Feb 5, 8:56 am, Phil Hobbs<pcdhSpamMeSensel...(a)electrooptical.net> > >> wrote: > >>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical feedback gizmo. > >>> I have some Stanley DN310s, but they've been discontinued. Other > >>> possibilities are: > > >>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ > >>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ > >>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs > >>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec > > >>> It would be really nice to find something with a flat front facet and > >>> (especially) lower capacitance, because it has to work at quite low > >>> currents (5-10 uA). > > >>> Any suggestions? > > >>> Thanks > > >>> Phil Hobbs > > >> Isn't low current and high speed mutually exclusive, like intelligence > >> and Republicans? > > > Nice try, Soup. ;) I enjoy talking electronics too much though. > > His "email address" always makes me crave miso soup and sushi. So, we > just went to the Japanese restaurant in town ... > > But this time I had pork teriyaki after the miso soup. We usually have > sushi in the evenings, I can't really work after that, it's so good that > I tend to eat too much of it. > > -- > Regards, Joerg > > http://www.analogconsultants.com/ > > "gmail" domain blocked because of excessive spam. > Use another domain or send PM. Sushi doesn't make for an evening meal. Just too light, even when supplemented with miso soup. It's better for lunch. Getting back to electronics., this is really an i=c*dv/dt issue. It seems to me all you can do is reduce C if current is limited.
From: Robert Baer on 6 Feb 2010 00:38 John Larkin wrote: > On Fri, 05 Feb 2010 11:56:15 -0500, Phil Hobbs > <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >> I need a fast IR LED (> 20 MHz, < 50 pF) for an optical feedback gizmo. >> I have some Stanley DN310s, but they've been discontinued. Other >> possibilities are: >> >> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs >> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >> >> It would be really nice to find something with a flat front facet and >> (especially) lower capacitance, because it has to work at quite low >> currents (5-10 uA). >> >> Any suggestions? >> >> Thanks >> >> Phil Hobbs >> >> PS: Amazing how we're actually talking about electronics at the moment! > > Maybe use a visible part? They seem to get the most development effort > lately. I'll measure the capacitance on some of the right-angle > surface-mount Osram parts we use. They are blindingly bright, clearly > on at 1 uA in normal office lighting. > > The red response of a silicon detector isn't much below the IR peak. > > And now, back to politics... > > John > Yes!! Bash them Russkies AKA REDs!
From: Robert Baer on 6 Feb 2010 00:46 John Larkin wrote: > On Fri, 05 Feb 2010 09:25:28 -0800, John Larkin > <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >> On Fri, 05 Feb 2010 11:56:15 -0500, Phil Hobbs >> <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >> >>> I need a fast IR LED (> 20 MHz, < 50 pF) for an optical feedback gizmo. >>> I have some Stanley DN310s, but they've been discontinued. Other >>> possibilities are: >>> >>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs >>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>> >>> It would be really nice to find something with a flat front facet and >>> (especially) lower capacitance, because it has to work at quite low >>> currents (5-10 uA). >>> >>> Any suggestions? >>> >>> Thanks >>> >>> Phil Hobbs >>> >>> PS: Amazing how we're actually talking about electronics at the moment! >> Maybe use a visible part? They seem to get the most development effort >> lately. I'll measure the capacitance on some of the right-angle >> surface-mount Osram parts we use. They are blindingly bright, clearly >> on at 1 uA in normal office lighting. >> >> The red response of a silicon detector isn't much below the IR peak. >> >> And now, back to politics... >> >> John > > > http://catalog.osram-os.com/catalogue/catalogue.do;jsessionid=6AC83F9F110FC71BC37646EE19F1BDDE?act=downloadFile&favOid=0200000200003436000100b6 > > I measured a red one of these at 9 pF, orange at 13.5. I have no idea > what the optical power output may be, or the ctr you can get into a > silicon detector. We consider 5 mA to be "bright" on the red and > green, 10 mA for the orange and blues. "Dim" is 1/10th that. > > These are really nice led's. The colors are bright and pure, the > orange being especially nice looking. And they are dual-shot moulded, > so they don't melt when you solder them. > > John > > Hmmm...try the Rohm SMT LED, 755-SML-P12YTT86 is the Mouser P/N. Seems rather bright at 50uA (it is yellow; there was a red one almost as good but do not remember the part number).
From: Robert Baer on 6 Feb 2010 00:53 John Larkin wrote: > On Fri, 5 Feb 2010 11:13:02 -0800 (PST), "miso(a)sushi.com" > <miso(a)sushi.com> wrote: > >> On Feb 5, 8:56 am, Phil Hobbs <pcdhSpamMeSensel...(a)electrooptical.net> >> wrote: >>> I need a fast IR LED (> 20 MHz, < 50 pF) for an optical feedback gizmo. >>> I have some Stanley DN310s, but they've been discontinued. Other >>> possibilities are: >>> >>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs >>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>> >>> It would be really nice to find something with a flat front facet and >>> (especially) lower capacitance, because it has to work at quite low >>> currents (5-10 uA). >>> >>> Any suggestions? >>> >>> Thanks >>> >>> Phil Hobbs >>> >>> PS: Amazing how we're actually talking about electronics at the moment! >>> >>> -- >>> Dr Philip C D Hobbs >>> Principal >>> ElectroOptical Innovations >>> 55 Orchard Rd >>> Briarcliff Manor NY 10510 >>> 845-480-2058 >>> hobbs at electrooptical dot nethttp://electrooptical.net >> Isn't low current and high speed mutually exclusive, like intelligence >> and Republicans? > > Ah, politics! > > I wonder why lefties always assume that conservatives are stupid. > That's the "what's wrong with Kansas?" dilemma, the lament that the > working class won't toe the party line and follow the lead of their > betters. > > Conservatives generally assume that lefties are both stupid and evil. > > John > It is not us poor "working" class no matter what "side", it is the politicians that are both stupid and evil. The US is bankrupt - it is a matter of how long it will take to manifest in a manner that CANNOT be lied away. And the Constitution is defunct courtesy of politicos since FDR stole our gold; they are working on stealing our guns via the UN now...
From: Robert Baer on 6 Feb 2010 00:55
miso(a)sushi.com wrote: > On Feb 5, 2:20 pm, Joerg <inva...(a)invalid.invalid> wrote: >> Phil Hobbs wrote: >>> On 2/5/2010 2:13 PM, m...(a)sushi.com wrote: >>>> On Feb 5, 8:56 am, Phil Hobbs<pcdhSpamMeSensel...(a)electrooptical.net> >>>> wrote: >>>>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical feedback gizmo. >>>>> I have some Stanley DN310s, but they've been discontinued. Other >>>>> possibilities are: >>>>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>>>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >>>>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs >>>>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>>>> It would be really nice to find something with a flat front facet and >>>>> (especially) lower capacitance, because it has to work at quite low >>>>> currents (5-10 uA). >>>>> Any suggestions? >>>>> Thanks >>>>> Phil Hobbs >>>> Isn't low current and high speed mutually exclusive, like intelligence >>>> and Republicans? >>> Nice try, Soup. ;) I enjoy talking electronics too much though. >> His "email address" always makes me crave miso soup and sushi. So, we >> just went to the Japanese restaurant in town ... >> >> But this time I had pork teriyaki after the miso soup. We usually have >> sushi in the evenings, I can't really work after that, it's so good that >> I tend to eat too much of it. >> >> -- >> Regards, Joerg >> >> http://www.analogconsultants.com/ >> >> "gmail" domain blocked because of excessive spam. >> Use another domain or send PM. > > Sushi doesn't make for an evening meal. Just too light, even when > supplemented with miso soup. It's better for lunch. > > Getting back to electronics., this is really an i=c*dv/dt issue. It > seems to me all you can do is reduce C if current is limited. Unprogram it with C#... |