Hi there - I was thinking about trying to design a laser driver over the weekend. Unfortunately, I can't seem to find a spice model for a laser diode, putting a bit of a squabash on that plan.
Anybody know where I can find one? Ideally I'd find one for a very normal ~5mw red laser diode - like those you'd find in a cheap laser pointer.
Thanks!
-Michael
I created a spice model for a purple laser diode, complete with it's optical sensor.
Heres an application note with some wxample models included.
Hi Winfield - out of curiosity, how would a purple laser diode differ from a red laser diode? (besides the outputted color :0 )
Thanks,
-Michael
Hi - Do you know how to import their part into LTspice? My only experience with spice is with using the built in library components - I've never had to work with the actual text files themselves :o
-Michael
Does not having a Spice model stop the project dead? I wonder how TVs and Radar were invented.
John
Any good reason that I have to have Flash installed to download this?
-- Paul Hovnanian paul@hovnanian.com ----------------------------------------------------------------------- Procrastinators: The leaders for tomorrow.
MUCH higher forward voltage - the band-gap voltage for short-wavelength photons is much higher, because each photon has much more energy. Also, every type of laser diode will have its own plot - the laser-light output is very nonlinear with current, and you want the spice model to properly show that effect. Also, whatever you get, I wouldn't trust the model until I had verified it on the bench.
Someone just downloaded the application notes PDF and used an example circuit? ;-)
-- Paul Hovnanian paul@hovnanian.com ----------------------------------------------------------------------- Procrastinators: The leaders for tomorrow.
Hi - Do you know how to import their part into LTspice? My only experience with spice is with using the built in library components - I've never had to work with the actual text files themselves :o
-Michael
Hello Michael,
Inside this zip-file is a model file laser_diode.lib . It contains a line .model dlaser D(...) Nothing great (Is=5e-37 N=1 ....). I doubt it's realistic, but it doesn't matter for your application. Just use it as it is.
Best regards, Helmut
25 of my 48 "professional" years designing circuits was BS... Before Simulators ;-)
I had ZERO design failure rate with breadboards... around 1% with simulators... although I must admit the simulated designs were FAR more complex than the breadboarded designs.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
Mine are still continuing because there are things that Spice don't catch. Then there are things that only Spice can catch (but not that frequently).
Now how was that with the switcher design of yours where you were 100% sure it would be bullet-proof? The one where El Capitan came in and rocked the power switch a few times, followed by a loud bang and molten solder flying about?
-- Regards, Joerg http://www.analogconsultants.com/
As others have said just build it. That's what I did for a client, didn't touch Spice during that project except for verifying one RF bandpass.
But watch out not to point the laser diode into eyes or other sensitive areas. Mind your pets, too. I've got a nosy Shepard checking out my stuff once in a while and she doesn't know that IR can be dangerous as well.
-- Regards, Joerg http://www.analogconsultants.com/
That was a breadboard ;-)
BTW, it wasn't El Capitan, it was the digital guru prick at GenRad ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
Hi Michael
I don't use LTSPICE. They do have a user group here
Someone there may have some pointers for you, or try sci.electronics.cad.
None that I know of its right from Cadence,there appnotes section.
I bet if you hadn't those 25 years with breadboards then the simulator failure rate would be a lot higher. The simulation can be only as good as the person's knowledge about the reality, plus the knowledge of the limits of the simulation.
Wiener (?) said that the computer is the amplifier for the brains, but not the replacement.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
There is a whole bunch of the different laser modulator ICs. Unless you are after some extraordinary parameters, there is no point to design the diode driver of your own.
Take a spice model of a diode and make it parameters to match the datasheet on the laser. BTW, "very normal" red laser diodes can actually belong to one of the two completely different types.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
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