Fast, efficient IR LEDs?
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From: John Larkin on 5 Feb 2010 13:45 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
From: George Herold on 5 Feb 2010 13:54 On Feb 5, 11:56 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 I have no part numbers to recommend. (Sorry) But I wonder why IR LEDs are so much more efficient than visible. (I calculate about 33% efficiency for the 850nm at 0.5W/A.) (O.5 W/A = 0.5 eV/electron and each photon is about 1.5 eV) George H.
From: miso on 5 Feb 2010 14:13 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?
From: Phil Hobbs on 5 Feb 2010 14:38 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 -- 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: John Larkin on 5 Feb 2010 14:43
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 |