Need 445 diode w/case pin

[jsyco]

Tried to post this a while ago but it didn't post ?

Does anyone know of any 445nM diodes with the case pin not clipped ? I have a friend that can make custom ceramic modules and or heatsinks , and I want to do some experimenting with these. I assume (am I wrong?:undecided that as the module will be non conductive I will need the case pin, thats why I ask.

 

[ElektroFreak]

Why would you need it? What would you connect it to? Anything touching the case is at the same potential as the case pin..

 

[jsyco]

EF thanks for the reply, but it does'nt help to answer my question with a question as I asked in my post if I was wrong in thinking I would need the case pin for a non cunductive module.

 

[ElektroFreak]

I'm not 100% sure what you're asking, but I'll try to elaborate.. The diode itself is isolated from the case by design, so to make an isolated module you don't need to connect the case to anything. Since the diode's case and whatever heatsink you use will all be isolated from the diode naturally, the module will be isolated. As far as conductive, since whatever heatsink you use will be metal it can conduct electricity, but to electrically isolate it you don't need to do anything.

 

[jsyco]

OK EF I am a little bit of a noob here and thats why I posted this. Not to be rude but you obviously did not read the original question as I stated clearly that this is to be used in a ceramic hence non metallic module.

The heatsink will also be ceramic.

 

[laser_freak]

On all the 445nm diodes I have the case pin is only partially clipped. You just need to take off the little, red, plastic pin holder thing by gently prying it up and off the pins. The case pin will be very short, but I was able to solder to it for one of my recent 445nm builds.

I'll try and take a picture tomorrow.

I'm also not sure why you need to case pin. With these 445nm diodes, you can leave the case pin unconnected or you can apply + or - voltage. It doesn't matter what you do with the case pin. The only reason I used the case pin in one of my builds was because drlava's microboost driver doesn't share the input ground with the output ground, and the host I was using was case negative. So I connected the case pin on the diode to the ground input on the driver.

 

[Alexizupinhea]

Well, reading other people's post confused me a little bit. Maybe I'm just really tired, but I'll try to make it in my own simple words...

This particular diode has three pins. One is for negative, one is for positive, and the third goes to case itself. Therefore, if the module will not be in a metallic heatsink, it would have no effect on powering up the diode itself. The two pins you need to connect to are long and not going to the case.

However, I may be wrong as I do not know the thermal properties of ceramic. However, accorind to this chart: Thermal Conductivity of some common Materials , Corian, which is ceramic filled, has a thermal conductivity of 1.06 whereas aluminum and copper are 250 and 401 respectively. Therefore, I would think it terrible to use ceramic as a heatsink. It may hold up to heat well, but I'm not sure it can conduct heat away from the diode rather than absorbing it and burning the diode out.

Please correct me if I'm wrong.

 

[jsyco]

I have a friend who works in a really high tech lab that works with new types of metallic ceramics. I don't know the math but according to him its thermal conductivity is ten time higher than aluminum, here is the formula he stated in his E-mail to me,(~180 W/mK, I have no idea what it states but I believe what he tells me. This is actally the same material used in the LED headlights Cadillac uses.


Best of all he is the guy in charge so as long as it can be considered R&D for an existing market he will make me some prototypes if I supply him with usable test data.

I work with corrian and it is mostly acrylic polymer.

 

[daguin]

LaserFreak is correct. The case pin is "clipped" in the installation into the projector. However, although shorter than the other pins, it is still there. It is long enough to be used. I solder to it all the time.

Remove the little plastic "spacer." You should see plenty of case pin for your use.

The diodes are NOT available to us from any other source (yet?)

Peace,
dave

 

[ElektroFreak]

OK EF I am a little bit of a noob here and thats why I posted this. Not to be rude but you obviously did not read the original question as I stated clearly that this is to be used in a ceramic hence non metallic module.

The heatsink will also be ceramic.

Sure enough you did, apologies.. there can be a lot to read here at times, sometimes I miss bits here and there.

The only thing I do is ground the case pin as I've found over time that it helps protect floating diodes from ESD discharges.. at least I haven't lost a floating-case diode to ESD since I started doing it about 3 years ago.

 

[Gryphon]

Your first post states that you need the case pin because the heatsink/module material you plan to experiment with is non conductive.

That said, you still don't need the case pin. The diode can(case pin) is electrically isolated from the laser die, and will behave no
differently then if it were installed in a copper host. You could install one of these diodes in a plastic module(no electrical conductance)
and it would still work because both the positive and negative pins on the diodes are there and isolated from the case.

I hope this answers your question

 

[daguin]

Your first post states that you need the case pin because the heatsink/module material you plan to experiment with is non conductive.

That said, you still don't need the case pin. The diode can(case pin) is electrically isolated from the laser die, and will behave no
differently then if it were installed in a copper host. You could install one of these diodes in a plastic module(no electrical conductance)
and it would still work because both the positive and negative pins on the diodes are there and isolated from the case.

I hope this answers your question

As long as you are not trying to run an electrical path through the diode case, the case pin is not used. Connect the positive and negative side of the driver to the power source and connect the positive and negative diode pins to the "out" side of the driver. Your diode will run electrically isolated from the case.

Peace,
dave

 

[jsyco]

Thanks to you all for your help on this. As I said I am a noob when it comes to this stuff and was not sure about the function of the case pin.

I'm going to send the aluminum heatsink to my buddy so a mold can be made to create the ceramic heatsink and I will let LPF know how it works out. I know there is not much need but think it would be nice to have a >1W 445 with a duty cycle measured in minutes.