Fast, efficient IR LEDs?
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From: John Larkin on 5 Feb 2010 14:46 On Fri, 05 Feb 2010 14:38:32 -0500, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >On 2/5/2010 1:45 PM, 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 >> >> >Hmm, interesting. The red ones specify about 7 lumens/W at 635 nm. The >photopic response there is about 22% of the peak value, or 138 lumens/W, >which makes these ones about 0.05 mW/mA, which is a bit on the low side. >I definitely like the capacitance though! > >Cheers > >Phil Hobbs Yeah, I guess 635 isn't red enough. John
From: Phil Hobbs on 5 Feb 2010 14:47 On 2/5/2010 1:37 PM, Joerg wrote: > Phil Hobbs 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? >> > > This one is too big, too much capacitance, but they have smaller plastic > versions, maybe give them a ring? How retro. ;) I'll do that, thanks. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Phil Hobbs on 5 Feb 2010 14:48 On 2/5/2010 2:13 PM, 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 >> > > Isn't low current and high speed mutually exclusive, like intelligence > and Republicans? > Nice try, Soup. ;) I enjoy talking electronics too much though. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Joerg on 5 Feb 2010 17:20 Phil Hobbs wrote: > On 2/5/2010 2:13 PM, 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 >>> >> >> 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.
From: Jim Thompson on 5 Feb 2010 17:25
On Fri, 05 Feb 2010 11:43:30 -0800, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Fri, 5 Feb 2010 11:13:02 -0800 (PST), "miso(a)sushi.com" ><miso(a)sushi.com> wrote: > [snip] >> >>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 ....lefties are both stupid and evil _and_ pathological liars. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 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. |